Plasma Science and Fusion Center
MIT's Plasma Science and Fusion Center (PSFC) is recognized internationally as a leading laboratory in developing the scientific and engineering aspects of magnetic confinement fusion and conducting cutting-edge research in plasma science and related technology. Research at the PSFC is carried out in 5 primary areas: fusion energy confinement research in the Alcator C-Mod tokamak, including investigations of the stability, heating, and transport properties of high temperature magnetically confined plasmas, as well as advanced tokamak research (AT); investigation of the basic physics of plasmas including magnetic reconnection experiments on the VTF facility, new confinement concepts such as the Levitated Dipole Experiment (LDX), development of novel high-temperature plasma diagnostics, novel diagnostic of inertial fusion experiments, basic laboratory and ionospheric plasma physics experiments, and theoretical research; a broad program in fusion technology and engineering development that addresses problems in several areas (e.g., magnetic systems, superconducting materials, fusion environmental and safety studies, and system studies of fusion reactors); a significant activity in developing environmental remediation techniques based on plasma technology, including industrial applications, and the physics of waves and beams (gyrotron and high gradient accelerator research, beam theory development, non-neutral plasmas, and coherent wave generation).
The PSFC R&D programs are supported principally by the Department of Energy's Office of Fusion Energy Sciences. There are approximately 245 personnel associated with PSFC research activities. These include: 18 faculty and senior academic staff, 48 graduate students and 7 undergraduates, with participating faculty and students from Electrical Engineering and Computer Science, Materials Science and Engineering, Mechanical Engineering, Nuclear Engineering, and Physics; 62 research scientists, engineers and technical staff, 58 visiting scientists and engineers, postdoctoral associates and research affiliates, 30 technical support personnel; and 22 administrative and support staff.
PSFC's research funding for FY2001 totaled $25.9-million, down slightly (1.4 percent) from $26.2-million in FY2000. Nearly 84 percent of the FY2001 total came from one sponsor—the Department of Energy's Office of Fusion Energy Sciences (OFES). Based in part on preliminary projections, we estimate that total funding in FY2002 will increase to $26.5-million. OFES funding in FY2002 is expected to decline by 3.8 percent relative to FY2001 (from $21.7million to $20.8million), but non-OFES related funding at the Center will increase by 35 percent during that same time period (from $4.2-million to $5.7million). The 35 percent increase in non-fusion related work is due in large part to an increase in funding from private industry in FY2002. These estimates are based on the U.S. Government's fiscal year which begins October 1.
An external visiting committee consisting of prominent members of the U.S. plasma science and fusion community met at MIT September 18-19, 2000 with the PSFC director, division heads, technical staff and graduate students to assess the overall state of research at the PSFC. In its summary report to MIT's Provost, Chancellor and Vice President for Research, the committee noted that "For several decades, the MIT plasma (science) and fusion effort has been one of international prominence. We are pleased to report that this world-class excellence continues today under the present center leadership, with the superb staff of scientists and engineers, and with unique experimental facilities. In essentially all major areas of its chosen research, the center is at the forefront internationally. MIT is to be commended for the foresight in developing the center and for its continuing support." The report went on to note that the decline in faculty count and the relative seniority of current PSFC-affiliated faculty are perhaps the most important issues facing the center at this time. The committee warned of a possible decline in prominence of the center if faculty staffing issues are not addressed in the near future.
The Alcator Project, led by Professor Ian Hutchinson and Dr. Earl Marmar, carries out experimental research on Alcator C-Mod, a compact, high-field high-performance divertor tokamak devoted to investigating the physics of high temperature magnetically confined fusion grade plasmas. The total staff of the Alcator Project is about 100. Two major collaborations, with the Princeton Plasma Physics Laboratory (PPPL) and the University of Texas at Austin continue to play important roles in the research program, and a large number of smaller collaborations with other institutions, both domestic and international, are also active collaborators in scientific research.
Experiments devoted to all of the major research topics on C-Mod were carried out during the twelve month period ending August, 2001, including Core Transport, Pedestal (edge) Physics, ICRF physics and development, high performance operations, and Divertor/SOL physics. Research into core transport and stability was concentrated on extending our understanding of double barrier discharges, which exhibit a core internal transport barrier with an H-mode (High Confinement) edge. The core barriers are reliably triggered by the application of off-axis ICRF heating, with the resonance located on the high-field side of the plasma. During the winter run period, we took advantage of our capability to operate 50 percent of our RF systems at tunable frequencies, so that the ITB could be triggered with the off-axis heating at one frequency while the core of the plasma, inside the barrier, could be heated at a different frequency. These experiments were started in December 2000, and continued in July 2001. A number of interesting physics results were obtained, and at present these phenomena are being analyzed with transport models and codes. Another significant result obtained in the July experiments was that the ITB could also be triggered with off-axis heating on the low field side; this result has important implications in regard to theoretical interpretation of these results.
Studies of the dynamics of the H-Mode edge pedestal were continued during the past year, with a strong emphasis on detailed, high spatial resolution diagnostic measurements in this region of the plasma. With increased total RF heating, and the achievement of high pressure gradients in the edge, small high frequency Edge Localized Modes (ELMs) appear in the pedestal region, on top of the quasi-coherent (QC) fluctuations (reported last year) which appear to control particle transport across the barrier region in the Enhanced D-alpha (EDA) H-Mode. In some cases, the QC mode appears to weaken, and the ELMing activity may take over as the arbiter of particle transport. In a related set of experiments, edge similarity studies, coordinated between C-Mod and the DIII-D tokamak in San Diego, obtained excellent comparison discharges, and the results indicate that the edge pedestal dynamics are probably dominated by plasma physics effects rather than atomic physics processes. In a new diagnostic effort, high speed imaging of edge fluctuations has revealed the time history dynamics of the small poloidal scale turbulence that is believed to dominate the transport (particularly for particles) in the region near to and outside (open field lines) of the separatrix. The images provide time history visualization of the structures, with resolution down to the microsecond range, and should lead to a significant increase of understanding of this important physical process, particularly through detailed comparison with numerical simulation.
At the end of the campaign, we carried out a set of experiments on long-pulse operation, primarily in preparation for the Lower Hybrid current drive, Advanced Tokamak investigations which will begin in FY2003. Inductively driven plasmas were investigated with total pulse length reaching 3.2 seconds. Physics experiments on these plasmas included investigations into divertor power loading and wall pumping/recycling evolution over the long pulse times.
A significant fraction of the project effort in the past 12 months has been devoted to modifying and improving the 4 strap (J-port) ICRF antenna. Substantial rework of the antenna was carried out in the period from January to April 2001, including a redesign of the feed straps located behind the antenna, to reorient them so that the RF electric fields are perpendicular to the magnetic field imposed by the tokamak coils and plasma current. In addition, changes were made to the plasma facing structures, to reduce the effects of RF-plasma interactions. These changes were highly successful, and allowed for substantial increases in the power levels which could be reliably coupled through the antenna to the plasma.
Beginning on August 6, the C-Mod facility entered an extended maintenance, inspection and upgrade period. During the next eight months, the TF magnet joints will be inspected, as was recommended by an engineering review panel. The inner divertor structure, and a portion of the inner wall tile support structure, is being replaced during this time. These inner wall changes will open up the space for shaping, particularly with regard to increased triangularity for lower X-point single null configurations, and at the same time will increase the strength of the structures, to allow for operation up to plasma currents of 2 MA.
The Physics Research Division, headed by Professor Miklos Porkolab, seeks to develop a theoretical and experimental understanding of plasma physics and fusion science. This division is also a base for developing basic plasma physics experiments, new confinement concepts, novel inertial confinement fusion diagnostics and space plasma physics experiments. In addition, this division is also the home for a strong base and supporting theory program.
Plasma Edge and Core Transport and Turbulence Theory
This group (Drs. P. Catto, J. Ramos and A. Simakov, and Mr. J. Hastie) studies the physics of turbulence, transport and stability related to plasma confinement experiments. The research relies on analytic investigations with numerical support aimed at understanding experimental observations from Alcator C-Mod and other tokamaks. It also includes theoretical support for the Levitated Dipole Experiment (LDX) being built at the PSFC in collaboration with Columbia University. Our research efforts this past year have focused on the following four key areas: a detailed proof that the induced electric field in C-Mod and other tokamaks is responsible for an additional poloidal plasma flow because of the presence of particles trapped in the magnetic field; a detailed evaluation and demonstration that the electric field just inside the separatrix of C-Mod and other tokamaks is set by the neutral viscosity for realistic neutral mean free paths, and that the neutrals can impact the poloidal flow of the ions; theoretical studies of global magnetohydrodynamic modes and the important edge localized Quasi Coherent Mode instability responsible for a benevolent regime of confinement in C-Mod; and a complete determination of the weakly collisional, long mean free path stability conditions for an equilibrium of arbitrarily high pressure plasma confined in a dipole magnetic field similar to that expected in LDX.
Advanced Tokamak Physics, MHD Stability, and RF Interactions
There have been four main thrusts to the work (of Drs. P. Bonoli, J. Ramos and M. Porkolab and Mr. J. Hastie) in this area in the past year.
- A study of mode conversion processes from the long wavelength magnetosonic (fast Alfvén wave) into short wavelength kinetic ion Bernstein waves in toroidal geometry using a full-wave electromagnetic field solver showed good agreement with experimental observations on C-Mod. Efforts are now underway to implement the field solver on a massively parallel platform under a new grant obtained through the Office of Fusion Energy Science.
- A generalization of the ballooning formalism to the analysis of high-toroidal-number, edge-localized external modes led to an analytic understanding of the instability range and growth rate of the "peeling" mode, which previously could only be obtained with two-dimensional codes.
- A two-fluid analytic model to investigate driven magnetic reconnection in collisionless or semi-collisional plasmas was developed which can describe the evolution of current layers and fast reconnection rates in the VTF experiment at the PSFC.
- A theory of electrostatic drift waves in a closed field line configuration such as the LDX experiment was developed which allows for a transition from collisional to collisionless regimes. The form of the stability boundary remains qualitatively unchanged, but the stable region narrows somewhat as the plasma collisionality is reduced.
RF Heating and Current Drive and Basic Plasma Theory
This effort, led by Professor A. Bers and Dr. A. Ram, obtained the following results:
- Derived symmetry relations during mode conversion processes based solely upon energy flow conservation and Onsager-like time reversibility properties of the full wave description of the fields. These symmetry relations show that emission from thermal electron Bernstein waves (EBWs) can be used to find optimal plasma edge conditions which will maximize the excitation of EBWs, from power sources external to the plasma, for plasma heating and current drive in high-beta tokamaks such as the Princeton NSTX experiment.
- On synergism in RF driven current with the bootstrap current-a problem of importance to the steady state operation of a tokamak confined plasma—an improved code for solving the drift kinetic Fokker-Planck equation with quasi-linear and neoclassical effects has been generated in collaboration with Dr. Y. Peysson of the CEA in Cadarache, France. Synergism is found in both lower hybrid and electron cyclotron driven currents.
- In relation to intense laser-plasma interactions of importance to inertial confinement fusion (ICF), graduate student Ron Focia, in collaboration with the ICF group at the Los Alamos National Laboratory, carried out a unique set of laser-plasma experiments in a single laser hot spot. The experiments showed unequivocally, and for the first time, the coupling of stimulated Raman scatter to the Langmuir decay instability with cascades, and a new type of electron acoustic wave. Analytical and computational studies have been undertaken to understand these results.
Levitated Dipole Experiment
The Levitated Dipole Experiment (LDX) represents a new concept exploration experiment sponsored by the Department of Energy and is initially funded as a five year research grant. LDX is a joint collaborative project with Columbia University and is located in Building NW21 at MIT. The principal investigators of this project are Dr. Jay Kesner of the MIT and Professor Michael Mauel of Columbia University. The LDX facility is being designed by the engineering division of the PSFC under the leadership of Dr. J. Minervini.
The levitated dipole experiment represents a new and innovative approach to magnetic fusion which will utilize a levitated superconducting coil to confine plasma in a dipole magnetic field. The concept was inspired by the observation that high pressure plasmas can be confined by planetary dipole magnetic fields, such as the magnetosphere which surrounds Jupiter. Compared with the traditional fusion approaches the levitated dipole may permit the confinement of higher pressure plasmas with reduced cross-field transport. The project has been funded as a five year grant with an approximate annual budget of $1.4 million, (shared between MIT and Columbia University). The construction of the project will take approximately four and a half years.
The design of the facility was largely completed during FY1998 and we are now nearing the end of the construction phase. The vacuum chamber is in place in the Tara cell of Building NW21, the high performance Nb3Sn floating coil has been successfully tested and is being installed within a cryostat and the high temperature superconducting levitation coil is under construction. Unfortunately, the startup of the experimental program has been delayed to the latter part of CY2002 due to a one year delay in the delivery of a large "charging" coil from Russia. When completed, LDX will be the only superconducting magnetic confinement experiment in the U.S. fusion research program.
Magnetic Reconnection Experiments on the Versatile Toroidal Facility (VTF)
Magnetic reconnection plays a fundamental role in plasma configurations because magnetic energy can only be released if the magnetic field line topology is changed. It controls the spatial and temporal evolution of explosive phenomena such as solar flares, corona mass ejections and internal disruptions in magnetic fusion devices. The basic plasma experiment led by Professor A. Fasoli and Dr. J. Egedal is now fully operational for the study of magnetic reconnection. Typically, 500 experimental plasma discharges are created per day when the VTF is operated. Due to the high reproducibility of the radio frequency (RF) generated plasmas it has been possible to measure the plasma response to reconnection with unprecedented accuracy. During driven reconnection events the collisionless plasma is characterized in terms of space and time evolution of magnetic fields, currents, density and electric potential. These experimental results have stimulated the development of new theoretical models for reconnection which will be tested experimentally in the near future.
MIT-PSFC/JET Collaboration on Alfvén Wave Instabilities
The MIT-JET collaboration is aimed at studying the interaction between non-thermal plasma particles and electromagnetic waves in the Alfvén range of frequencies on the JET tokamak. The interaction between plasma waves and fast particles such as fusion produced alphas is one of the critical issues to understand the behavior of burning tokamak plasma and can be studied on the reactor-relevant JET plasmas. During the last experimental campaigns on JET, a number of dedicated experiments have been performed and have led to significant progress in the understanding of the possible stabilization mechanisms of Alfvén Eigenmodes. These results have contributed to improving the theoretical understanding of the physics of the interaction between high energy particles (such as alpha particles) and Alfvén waves in thermonuclear fusion plasmas. In addition, a project for the development of new dedicated antennas for the excitation of electromagnetic waves has been prepared and has been presented to the relevant EFDA-JET Committee, receiving a very favorable assessment.
Inertial Confinement Fusion Experiments
MIT's effort in inertial confinement fusion, led by Dr. Richard Petrasso, is a collaboration with the University of Rochester and Lawrence Livermore National Laboratory. This program has continued to produce exciting results on experiments conducted at the OMEGA laser facility at the Laboratory for Laser Energetics at the University of Rochester. MIT has been responsible for designing and implementing two very large charged-particle spectrometers, and nine smaller ones.
Such spectrometers are used to detect charged fusion products that are generated at the core of imploding ICF capsules. From the number of such reactants (i.e. the yield), the effectiveness of the fusion process can be determined, and from the energy loss of the reactants, as they pass through the capsule, a measure of the capsule compression can be determined. Both these quantities, yield and capsule compression, are fundamental parameters needed to characterize the quality of the implosions. In addition, since the spectrometers view the implosion from many different angles, the implosion symmetry can be sensitively studied. In fact in recent work nine different spectrometers viewed imploding capsules and showed that significant non-spherical asymmetries exist. MIT data and analysis have contributed important insights into the relationship between experimental conditions and implosion performance and in doing so has advanced the state of ICF research. These spectrometers are prototypes for those being designed by MIT and collaborators for the National Ignition Facility (NIF) at Lawrence Livermore. For example, at the core of NIF implosions, we expect to achieve plasma densities that are 6 times larger than the density at the center of the Sun, or 52 times more dense than gold. Currently, the MIT/PSFC has the lead role in organizing and coordinating the Basic Science Users Group for the National Ignition Facility.
Novel Diagnostics for Magnetic Fusion Research
The Phase Contrast Imaging diagnostic (Professor M. Porkolab and Dr. C. Rost) was operated throughout the DIII-D tokamak 2001 experimental campaign, and analysis of the data is ongoing. New results and upcoming plans include the following:
- Turbulence measurements made by the PCI of otherwise identical plasmas with reversed magnetic geometry showed a change in the radial fluctuation propagation from inward to outward—this is a valuable clue in understanding the effects of velocity shear and magnetic geometry on tokamak edge fluctuations.
- Wavelet analysis of PCI measurements of edge localized modes (ELMs) has improved the time resolution of the measurement of the fast evolution of this complex phenomenon and will allow comparison with models of the initial linear phase.
- In response to a call for new proposals, a proposal has been submitted to the U.S. Department of Energy to upgrade the diagnostic to detect the high-frequency short-wavelength modes (Electron Temperature Gradient, or ETG modes) associated with the transport of electrons across the magnetic field lines. There is currently no diagnostic on any tokamak which performs such measurements. The upgrade will include moving the position of the diagnostic on the tokamak, changing the optics, and using faster electronics.
In other diagnostics work, the Plasma Technology Division (Dr. P. Woskov) continues research on the development of Collective Thomson Scattering (CTS) for energetic ion measurements in tokamaks. Recent developments at the JET (England) and TEXTOR (Germany) tokamaks have demonstrated the richness of energetic ion information provided by CTS. It has been shown that energetic ion localization, energy distribution and direction can all be determined in tokamaks to a degree not possible by other diagnostic techniques. A broad international collaboration is being planned for implementation on the ASDEX tokamak in Garching, Germany, using high frequency gyrotrons. A new proposal has been submitted to DOE, Office of Fusion Energy Sciences, to fund this upgraded program.
Ionospheric Plasma Research
Initial ionospheric plasma RF heating experiments have been conducted by Professor Min-Chang Lee (Visiting Scientist from Boston University) and his students in Alaska, using DoD's HF Active Aurora Research Program (HAARP) facility. These experiments are aimed at investigating ionospheric plasma turbulence and developing ELF/VLF communications schemes for high efficiency and good quality signals. In a new project, PSFC's Ionospheric Radar Integrated System (IRIS), after having been successfully tested last year, will be deployed for remote sensing of space plasmas during experiments in Alaska, Massachusetts, and Puerto Rico. A proposal was recently submitted for a DoD equipment grant, to acquire an optical instrument known as All Sky Imaging System (ASIS), which can exhibit spatial structures of plasma turbulence. ASIS together with IRIS will provide powerful diagnoses of RF heated plasmas in space experiments.
The Waves and Beams Division, headed by Dr. Richard Temkin, conducts research on novel sources of electromagnetic radiation and on the generation and acceleration of particle beams. Substantial graduate student involvement is emphasized in all research programs within the Division.
The gyrotron is a novel source of microwave, millimeter wave and submillimeter wave radiation. Gyrotrons are under development for electron cyclotron heating (ECH) of present day and future plasmas, for high frequency radar and for spectroscopy. These applications require tubes operating at frequencies in the range 90-500 GHz at power levels of up to several megawatts. Dr. Michael Shapiro leads the Gyrotron Research Group. In 2001, we have begun testing a new 110 GHz gyrotron oscillator intended to operate at the 1 to 1.5 MW power level. The new gyrotron will be tested at both MIT and at an industrial vendor, Communications and Power Industries of Palo Alto, CA. The MIT gyrotron will operate in 3 microsecond pulse lengths while the industrial tube should be capable of continuous wave (CW) operation. Research challenges include operation of the gyrotron in stable, single-mode oscillation without mode competition; production of a high quality electron beam; achievement of high interaction efficiency in the resonator and achievement of very high overall efficiency (>50 percent) when operated with a depressed collector.
In gyrotron research, it is also critical to have a high efficiency mode converter that can transform the output mode of the gyrotron into a Gaussian beam in free space. In recent years, we have been studying the measurement of the phase distribution in microwave beams using a phase retrieval algorithm based on the measure field amplitude on a series of planes. In 2001, we have completed the first demonstration of a new approach to determining the phase distribution in the beam. This method uses the measured field amplitude on a series of planes but relies on calculated moments of the field amplitude to determine the parameters of a polynomial expansion of the spatial phase distribution. This irradiance moment method, which has been previously used at optical wavelengths, is being applied to microwave frequencies for the first time at MIT. The method will be applied to design single mirror correctors for the gyrotrons at General Atomics in San Diego. A new idea for a gyrotron microwave window, a dome shaped window, is also under investigation. This research is primarily sponsored by MIT Lincoln Lab through their Advanced Concepts Committee (ACC) internal funding program. Dynamic tests of this window, at high pressure and temperature, have been completed in 2001. The results show that the dome window concept is capable of operation at up to 1 MW of power.
In 2001, a new concept in vacuum electron devices (or microwave tubes) was demonstrated, namely a photonic bandgap (PBG) cavity gyrotron. Recently, the Gyrotron Research Group has demonstrated a new technique for building high frequency microwave sources with resonator dimensions many times the operating wavelength. In traditional larger dimension resonators, the electron beam can excite many resonant modes at once. The resulting output is very inefficient and is not useable. The novel resonator in the MIT experiment was made of a photonic band gap (PBG) structure, a two dimensional array of metal posts which reflects only certain frequencies while being transparent to other frequencies. This allows a much larger sized resonator to support only one higher order mode while eliminating all other unwanted modes in the vicinity of the operating mode. Output power of 25 kW at 140 GHz was achieved in the desired with no competing modes observed over a 30 percent frequency range. This research received special notice in Physical Review Focus, the Boston Globe Science Section and Laser Focus World magazine.
Intensive research continues on a 250 GHz gyrotron for use in electron spin resonance and nuclear magnetic resonance studies. Reliable operation for many hours was achieved this year with operation at CW power levels of up to 25 W and pulsed power levels of up to 100 W. This research, funded by NIH in collaboration with Prof. Robert Griffin of the Magnet Lab, is a pioneering effort in high frequency electron spin resonance studies. Signal enhancements of sixty have been demonstrated in initial NMR experiments. A new gyrotron operating at the second harmonic was designed in 2001 for use in a new NMR spectrometer. The gyrotron, designed to operate at 460 GHz, will be used in conjunction with a 17 T magnet system recently installed at the Francis Bitter Magnet Laboratory. The 460 GHz gyrotron design has been completed and the long lead time items, including a superconducting magnet have been ordered. This gyrotron is expected to operate in 2002. In a new program, we have been funded as part of a DoD MURI consortium for Innovative Vacuum Electronics. A 95 GHz amplifier is being constructed with first tests planned at 140 GHz using available equipment. A gyrotron amplifier with a confocal waveguide structure has been built and will be tested in 2002.
High Gradient Accelerator Research
The High Gradient Accelerator Group is conducting research on a novel, 17 GHz, microwave driven, photocathode electron injector. This device, sometimes called an RF gun, can generate a 2 ps beam of 1-2 MeV, 50-500 A electrons at high repetition rate. A 26 MW, 17.1 GHz klystron power source drives the electron gun. The electron beam can be directly applied to microwave generation experiments or it can be used as an injector into a 17 GHz, high gradient accelerator. This research supports the program to build new electron accelerators that can reach the TeV range of energies. In 2001, the emittance of the electron beam from the RF photocathode gun has been measured to be 3 (pi) mm mrad for a 50 pC electron bunch, close to a record high value of beam brightness. A new electron gun that can achieve higher electron beam energies, over 2 MeV, and higher beam quality has been designed, built and tested. Results indicated that high order, quadrupole modes need to be eliminated in order to achieve improved beam brightness. Commissioning continued in 2001 of the Haimson Research Corp. 17 GHz electron accelerator. This is the highest power accelerator on the MIT campus and the highest frequency stand-alone accelerator in the world. One potential application of this accelerator is in free electron laser research. Improvements to the 17.1 GHz klystron have been made in 2001 to secure reliable operation at power levels of at least 15 MW at 17.14 GHz. The operation of the accelerator has been successfully simulated using advanced codes. This research program should establish 17 GHz as a feasible frequency for future TeV electron colliders.
Theoretical Research in Beams and Non-neutral Plasmas
The Intense Beam Theoretical Research Group, led by Dr. Chiping Chen, has contributed very significantly to our understanding of coherent radiation generation and particle acceleration. Topics covered include coherent radiation sources (crossed-field devices, CARM, FEL, gyrotron, relativistic klystron, relativistic TWT), intense electron and ion beam transport, mechanisms and control of beam halo formation, cyclotron resonance accelerators, photocathode design, and related topics. Research explores self-field-induced nonlinear resonant and chaotic phenomena in intense charged particle beams. This research supports the U. S. program to construct advanced accelerators for such applications as nuclear waste treatment, heavy ion fusion and free electron lasers. In 2001, a new Green's function based modeling technique was applied to studies of self-fields in bunched electron beams in such high-power klystrons as those that are being developed at the Stanford Linear Accelerator Center (SLAC) for driving the Next Linear Collider (NLC). A Photonic Band Gap Structure Simulation (PBGSS) code was written and applied in the modeling and design of photonic crystal based active radiation devices. A breakthrough was made in the understanding of high intensity sheet beams. Also gained is a better understanding of the equilibrium and confinement of bunched annular beams in high-power microwave sources.
The objectives of the Plasma Technology Division, led by Drs. Daniel Cohn and Paul Woskov, are to develop new fusion spin-off applications, particularly in the environmental and energy efficiency area; to develop new fusion diagnostics; and to develop new fusion reactor system concepts. A major thrust is in the area of plasma aided conversion of hydrocarbon fuels into hydrogen. Hydrogen has potential environmental advantages as a fuel or a fuel additive that can greatly reduce pollution from vehicles and stationary electricity generation systems. It can also be used to increase the efficiency of conversion of hydrocarbon fuels into mechanical power or electrical power. The use of hydrogen can facilitate high efficiency, lean burn spark ignition engine operation. It can be used in high efficiency fuel cells for electricity generation.
One project in the area of plasma aided conversion of hydrogen into hydrocarbon fuels investigates the use of plasmatron devices for manufacturing hydrogen for use in stationary fuel cell facilities. A second project, which is the major activity, is investigating the vehicular use of compact plasmatron devices for onboard conversion of gasoline into hydrogen-rich gas. The hydrogen-rich gas would then be combusted in a slightly modified spark ignition engine. Using the hydrogen-rich gas as an additive to gasoline, large reductions in NOx,, a major air pollutant, can be obtained. By facilitating high compression ratio lean burn operation, the use of hydrogen rich gas could also increase net engine system efficiency by up to 25 percent. The modified engine system including the plasmatron devices could have a cost as low as $500. Fuel savings could result in a payback time of as short as two years. The rapid payback time could potentially make possible widespread implementation on cars and light duty vehicles which could eventually lead to a gasoline savings in the United States of 20 billion gallons a year. A major program in collaboration with Professor John Heywood of the Mechanical Engineering Department and the Sloan Automotive Laboratory is being initiated with support from Arvin Meritor, a leading global manufacturer (headquartered in Troy, MI) of exhaust systems and other automotive systems. A third project investigates the use of plasmatron generated hydrogen as a means to improve catalytic reduction of diesel engine exhaust.
The Plasma Technology Division is also investigating the use of millimeter wave reflectometry and pyrometry for measurement of the properties of glass produced in vitrification of radioactive waste. The objectives of this technology development effort is to contribute to DOE environmental management needs of maximizing glass loading, optimizing durability of long-stability glass, and reducing long-term storage volumes. The technology earned an R&D 100 Award as one of the most significant new technologies in 2001.
The Technology and Engineering (T&E) Division, headed by Dr. Joseph Minervini, conducts research on conventional and superconducting magnets for fusion devices and other large-scale power and energy systems.
As usual, the major emphasis of the Division's effort has been on support of the U.S. Fusion Program where the PSFC has the leadership responsibility for the Magnets Enabling Technology program. A major effort was devoted to analysis of the large amounts of data generated by the successful testing of the Central Solenoid Model Coil (CSMC) in 2000 at the Japanese Atomic Energy Research Institute (JAERI) in Naka, Japan. Collaboration with JAERI continued on this project with Dr. Philip Michael participating in the installation of the next Toroidal Field Coil Insert module (TFCI) in Naka. The Division's lead experimentalist, Dr. Makoto Takayasu is now at the test site participating in the TFCI test program, while data is simultaneously being transferred to MIT and analyzed here.
Professor Ronald Ballinger continued materials development on the superalloy Incoloy Alloy 908 in the Materials Science and Technology Laboratory of the Technology and Engineering Division. Most recent research is focused on modifications to the Alloy 908 to reduce oxygen embrittlement sensitivity during high temperature reaction heat treatment of the superconductor.
The division continued to play an important role in technology development of magnet systems and in quadrupole magnet array design studies for the Lawrence Berkeley National Laboratory's High Current Transport Experiment (HCX) and the Integrated Research Experiment (IRE). HCX and IRE are the main elements of the US Heavy Ion Fusion Driver program, a major focus of Inertial Fusion Energy (IFE) research. During the past year, in addition to the design studies and quadrupole analysis, the division tested two superconducting quadrupole coils fabricated in industry as prototypes for the HCX, and performed data analysis of the coil performance.
Manufacturing of the magnet systems for the Levitated Dipole Experiment (LDX) continued during this past year. Major components of the cryostat for the Nb3Sn Floating Coil (F-Coil) were completed. Fabrication of the Charging Coil (C-Coil) continued at the D.V. Efremov Scientific Research Institute of Electrophysical Apparatus in St. Petersburg, Russia. Division staff are monitoring the design and fabrication process. The high temperature superconductor (HTS) tape was delivered and fabrication of the Levitation Coil (L-Coil) was begun in industry.
The division provided engineering support to the Princeton Plasma Physics Laboratory in the evaluation of Next Step Options for the US Fusion Program and in the design of the Fusion Ignition Research Experiment (FIRE). MIT continues to play a lead role in the magnet system design, cryogenic system design, and structural design for the FIRE as well as systems level studies.
Research continued under sub-contract to the Samsung Advanced Institute of Technology for magnets and magnet systems design for the Korean K-STAR superconducting tokamak program.
In the area of technology support for the high energy physics program, the division was the successful bidder for the NSF funded "Conceptual Design Study for a Muon-Electron Conversion (MECO) System of Superconducting Solenoids." This is a very large system of complex superconducting magnets that will form the core of the MECO experiment to be located at the Brookhaven National Laboratory. The contract origin is the University of California-Irvine where the lead investigator for the MECO collaboration is located. Approximately two man-years of effort are being applied by the T & E Division, including internal collaboration with Professors Joseph L. Smith, Jr., and John Brisson from the Department of Mechanical Engineering. We believe there will be follow-up funding in FY2002 for overseeing detailed design and procurement of the magnet system in industry.
A small design effort was carried out this year for the superconducting magnet system for the "Neutrino Factory." as part of a collaborative proposal submitted through Brookhaven National Laboratory to DOE. We have received an expression of interest from BNL to perform the design of an early phase pulsed, nitrogen-cooled copper magnet for this project. We hope to carry out that project early in FY2002 by collaborating with engineers from the Alcator Division.
The division continued it's important role in design and development of proton radiography superconducting quadrupole focusing magnets for the Advanced Hydrodynamic Facility (AHF) being designed at the Los Alamos National Laboratory. More detailed design was performed this year on the large bore superconducting magnets. This should lead to an expanded role for MIT in FY2002 for development in industry of some prototype magnets.
The division has contracts as the Research Institution for two NASA funded STTRs, in collaboration with the Advanced Magnet Laboratory, Inc., a Florida based small business. We are now performing a Phase II design of the superconducting model coils for an electromagnetic catapult, "MagLifter", to lower the cost of cargo delivery to space. We are performing the conductor and coil design and will test the coils at MIT after AML fabricates them. We are also working on another joint Phase-I STTR from NASA to study a superconducting magnetic energy storage system (SMES) as a pulsed power source for the MagLifter launch concept.
A proposal was submitted to NASA for a Cooperative Agreement on HEDS Technology Development/Commercialization Initiative. The project title was "Development of Advanced, Lightweight Superconducting Magnets for Plasma Rockets," to be performed in collaboration with the Advanced Space Propulsion Laboratory at the Johnson Space Center. Although we were successful in being notified by NASA that our proposal was accepted for funding, changes in the FY2001 budget for NASA did not allow them to fund any of the accepted proposals. We are hopeful that we can resubmit again in FY2002 if the program funding is returned.
A proposal was resubmitted to NIH for the development of a new device to separate blood components for therapeutic purposes by use of magnetic separation. The NIH review gave very good results and we are hopeful that we will be notified of funding award this October.
The Plasma Science and Fusion Center's educational outreach program is planned and organized under the direction of Mr. Paul Rivenberg, Communications and Outreach Administrator of the PSFC. The program focuses on heightening the interest of K-12 students in scientific and technical subjects. The PSFC seeks to educate local students and the general public by conducting general tours of experiments being done here. Special "Outreach Days" are held twice a year, encouraging high school and middle school students from around Massachusetts to visit the PSFC for a day of hands-on demonstrations and tours.
The Mr. Magnet Program, headed by Mr. Paul Thomas, is completing its ninth year of bringing lively demonstrations on magnetism into local elementary and middle schools. This year Mr. Magnet presented the program to over 30,000 students at over 77 schools and other events, reaching students from Kindergarten through college freshmen. He makes a special effort to encourage girls to consider a science-related career. In Spring 2001 Paul Thomas traveled with his truckload of equipment to Washington, DC, at the request of the Department of Energy, to involve participants of the DOE National Science Bowl with his hands-on magnetic experiences. While there he took the occasion to visit schools in the Germantown, MD area, inviting DOE sponsors to observe his program in action. To supplement his traveling show, Paul is creating a number of specialized workshops at the PSFC, In the summer of 2001 he will be guiding a class of middle school students through the process of creating their own electromagnets.
Paul Thomas also contributed to the success of the MIT Museum's "Thinkapalooza" exhibit, which opened in the Fall of 2000. Paul created a wonderful big toy that curious students can use to create plasmas, and see how they change when different gases and different frequencies are used. The demonstration has remained a part of the MIT Museum exhibit even after the Thinkapalooza show ended. Paul Rivenberg collaborated with MIT Museum staff to organize this effort, and brought in Administrative Assistant Mary Pat McNally to contribute graphic designs.
The PSFC continues to work with other national laboratories to educate students and the general public. An annual Teacher's Day (to educate teachers about plasmas) and Open House (to which they can bring their students) has become tradition at each year's APS-DPP meeting. Paul Rivenberg and Research Scientist Réjean Boivin aided organizers of the 2000 education events in Québec, which attracted over 150 teachers, and received much attention from the Québec press. Mr. Rivenberg continues to work on similar events scheduled for Long Beach (APS-DPP meeting, fall 2001) and Atlantic City (IEEE meeting, fall 2001). At these events the PSFC plans to bring an improved version of their "C-Mod, Jr. Video Game," which teaches students about how we confine plasmas in a tokamak. It will be upgraded with the help of PSFC graduate students in the summer of 2001. Paul Thomas is also working on a portable plasma demonstration to bring to the APS-DPP meeting.
Technical Supervisor Robert Childs, as part of the American Vacuum Society Meeting in Boston (October, 2000), helped organize a science education workshop for teachers who attended the conference. Attendees met at the PSFC where they received instruction, as well as tours of the facilities.
The PSFC continues to be involved with educational efforts sponsored by the Coalition for Plasma Science (CPS), a growing organization formed by members of universities and national laboratories to promote understanding of the field of plasma science. Associate Director Dr. Richard Temkin, who oversees PSFC education efforts, is working with this group on goals which include requesting support from Congress and funding agencies, strengthening appreciation of the plasma sciences by obtaining endorsements from industries involved in plasma applications, and addressing environmental concerns about plasma science, particularly fusion. This year CPS sponsored a well-attended congressional luncheon in Washington, DC, during which NASA Astronaut and former MIT PSFC Visiting Scientist, Dr. Franklin Chang-Diaz, explored the topic of plasma propulsion for space travel. Paul Rivenberg has continued his duties as editor of the Coalition's Plasma Page, a summary of plasma-related news items of interest to the media. Mr. Rivenberg also heads a subcommittee which this year created a web site to help teachers bring the topic of plasma into their classrooms. The site will continue to improve and expand. Paul has also joined the Technical Materials subcommittee, where he oversees content and design of two-page information sheets that will introduce the layman to different areas of plasma science.
During the past year, there have been a number of appointments and promotions in Plasma Science and Fusion Center program areas.
Alcator Division: Mr. Xiwen Zhong was appointed Research Engineer; Mr. Richard Murray RF Instrumentation Engineer; and Dr. Yijun Lin Postdoctoral Associate.
Physics Research Division: Dr. Peter Catto was appointed Senior Research Scientist as well as Assistant Director and head of the PSFC Theory Program; Dr. Andrei Simakov was appointed Postdoctoral Associate, and Ms. Ayse Bilgin was appointed Research Specialist.
Waves and Beams Division: Dr. Michael Shapiro was appointed Research Scientist.
In the Administrative area, Mr. John Defandorf was appointed Assistant Fiscal Officer.
Alcator Division: Dr. Martin Greenwald was promoted to Senior Research Scientist; Dr. John Rice to Principal Research Scientist; and Mr. Rui Vieira to Chief Mechanical Engineer.
Physics Research Division: Dr. Abhay Ram was promoted to Principal Research Scientist and Drs. Jan Egedal-Pedersen and Jon Rost Research Scientists.
Technology and Engineering Division: Dr. Joseph Minervini was promoted to Senior Research Engineer.
In the Administrative area, Mr. Jason Thomas was promoted to Library Administrator.
During the past year, the following departments granted students degrees with theses in plasma fusion and related areas:
- Nuclear Engineering: Nathan Dalrymple, Ph.D.; Seung Kee Min, Ph.D.; George Haldeman, Ph.D
- Physics: Yijun Lin, Ph.D.; Alexander Mazurenko, Ph.D.; Andrei Simakov, Ph.D.
More information about the Plasma Science and Fusion Center can be found online at http://www.psfc.mit.edu/.