MIT Reports to the President 1994-95

PLASMA TECHNOLOGY AND SYSTEMS DIVISION

The Plasma Technology and Systems Division, headed by Dr. Daniel R. Cohn, investigates plasma processing for environmental and industrial applications; develops new diagnostic technology for environmental and fusion applications; and investigates advanced fusion reactor systems designs and magnet concepts. Current research areas include arc plasma treatment of solid waste (Daniel R. Cohn, Paul P. Woskov, Charles H. Titus, and Jeffrey E. Surma); process diagnostic development (Paul P. Woskov and Daniel R. Cohn); cold plasma processing of gaseous waste (Daniel R. Cohn and Leslie Bromberg); plasma manufacturing of hydrogen (Daniel R. Cohn and Leslie Bromberg); millimeter wave and infrared diagnostic development (Paul P. Woskov); system studies (Leslie Bromberg); high temperature superconducting magnet development (Leslie Bromberg); and fusion safety and environmental studies (Mujid S. Kazimi). Some highlights of our research in the past year are listed below.

Arc Plasma Furnace Treatment Of Solid Waste

A pilot-scale arc plasma research furnace to study treatment of simulated solid waste has been operated with continuous feed. Power levels in the 250 kW range were used with a material feed rate of 200 pounds per hour. Soil characteristic of the Idaho National Engineering Laboratory (INEL) has been converted into a stable glass. The furnace has also been used for extensive testing of process diagnostics. Future objectives include studies of vitrification of a range of simulated wastes; development of predictive models and their applications to control systems (with Prof. Julian Szekely of the Materials Science and Engineering Department); and component testing.

Process Diagnostics For Waste Treatment

An active millimeter-wave pyrometer has been developed to measure furnace and material temperatures in a hostile environment. The device has been successfully tested in the Mark 2 furnace. A 1994 R&D 100 Award was received for this work. A microwave plasma analyzer for continuous monitoring of metals in smoke stack emissions has also been successfully tested on the Mark 2 furnace. A 1995 R&D 100 Award for this technology has been announced recently. In addition to application to waste treatment in plasma furnaces, the capability for continuous monitoring of metals emissions could be applied to incinerators, waste to energy plants, and fossil fuel power plants.

Low Temperature Plasma Treatment Of Gaseous Waste Streams

We have shown in the laboratory that low temperature plasmas generated by moderate energy (100-300 keV) electron beams can be used to selectively destroy dilute (1-1000 ppm) concentrations of volatile organic compounds (such as carbon tetrachloride and trichloroethylene) in air streams. The high degree of selectivity results in a highly efficient relatively low cost process. This system is attractive to DOE for on-site treatment of solvents pumped out of the ground in remediation activities and is also attractive for air stripping of contaminated water. In 1995, a successful initial field test was carried out at the DOE Hanford site. The test showed fully automated feedback controlled operation.

Plasma Manufacturing Of Hydrogen

Support from the DOE Hydrogen Research Program has been received in 1995 for investigations of plasma manufacturing of hydrogen. Experiments are underway to determine the effectiveness of arc plasma technology in converting hydrocarbons into hydrogen-rich gas. Potential applications include use with fuel cells. Prof. Simone Hochgreb from the Mechanical Engineering Department is participating in this activity.

Plasma Diagnostics Development

A gyrotron scattering system for alpha particle diagnostics has been tested on the TFTR tokamak at Princeton University. Scattering from relatively high level nonthermal fluctuations was observed, which has prevented a simple interpretation of these results. Meanwhile, collaborative efforts in scattering experiments are also underway with the JET tokamak in Abingdon, England. This activity, which will use a high power Russian gyrotron operates in a different regime, has good prospects for making the first thermal scattering measurements from alpha particles. These measurements are important for understanding ignition physics and could play a key role in ITER.

WAVES AND BEAMS DIVISION

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.

Gyrotron Research

The gyrotron is a novel source of microwave, millimeter wave and submillimeter wave radiation. It uses a helical electron beam in a high magnetic field to generate radiation by stimulated emission at the electron cyclotron frequency. Gyrotrons are under development for electron cyclotron heating (ECH) of present day and future magnetically confined fusion plasmas as well as for high frequency radar. These applications require tubes operating at frequencies in the range 100-300 GHz at steady-state power levels approaching 1 MW. The gyrotron research group is led by Dr. Kenneth Kreischer.

Research has concentrated on investigating the physics issues which affect the efficiency of operation of high power, high frequency gyrotrons. Efficiency is a critical issue because it determines the recirculating power needed to sustain a practical fusion reactor and also greatly impacts the reliability and cost of plasma heating systems. We have begun a program of research to demonstrate a high power, high frequency gyrotron suitable for application to the International Thermonuclear Experimental Reactor (ITER). A prototype experiment at M. I. T. has been built and is now under first testing. The ITER Joint Central Team has approved the research phase of this project for credit as part of the ITER program. The objective is to demonstrate a 1 MW, 170 GHz gyrotron with an efficiency of at least 35%. This work will be carried out in collaboration with Varian Associates, General Atomics, Univ. Wisconsin, Univ. Maryland and Lawrence Livermore National Lab. The MIT gyrotron group has the lead role in this effort.

A program of research is also underway to demonstrate a coaxial cavity gyrotron. This experiment will be carried out at 140 GHz in collaboration with Dr. Michael Read of Physical Sciences, Inc. of Alexandria, Virginia. In principle, the coaxial cavity gyrotron may be capable of power levels up to 3 MW, significantly higher than the 1 MW power expected from conventional cavity gyrotrons. The experiments will begin in the summer of 1995.

Relativistic Beam Physics Research

The Relativistic Beam Physics Group, led by Dr. Bruce Danly, investigates the generation of high voltage electron beams and their application to high power microwave generation. Research programs include investigations of the cyclotron autoresonance maser (CARM), the free electron laser (FEL), the relativistic klystron and the induction linear accelerator (ILAC).

Research is continuing on a high power, 17 GHz klystron in collaboration with Haimson Research Corp. of Palo Alto, CA. The klystron electron gun is a gun that was previously built for MIT and the klystron cavities were built by Haimson Research. The klystron has now demonstrated power levels of up to 26 MW in 1 us pulsed operation using a 560 kV, 95 A beam. These are record power levels for a relativistic klystron operating at such a high frequency in pulse lengths in the us range. An efficiency as high as 51% was achieved. Work is continuing on optimizing the klystron performance and applying it to high gradient acceleration experiments.

High Gradient Accelerator Research

The High Gradient Accelerator Experiments Group led by Dr. Shien Chi Chen is preparing a novel, 17 GHz microwave driven, photocathode electron injector. This device, sometimes called an RF gun, can generate a 2 ps beam of 2-3 MeV, 50-500 A electrons at high repetition rate. A 17 GHz klystron power source will drive the electron gun. This 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 which can reach the TeV range of energies.

The RF gun experiment has been operated with a microsecond pulse length klystron source at power levels of 5 to 10 MW at 17.145 GHz. The power coupled into the electron gun was monitored using the forward and reflected microwave power. A stored field equivalent to an on-axis accelerating gradient as high as 150 MeV/m was obtained, a record high value. Work is also progressing on generating the required laser pulse for the photocathode. This pulse must be timed to an accuracy of 1 ps in order to coincide with the 17 GHz accelerator field at a phase accurate to within 6 degrees.

Theoretical Research

A new research program has been initiated by Dr. Chiping Chen on the topic of theoretical and computational investigation of periodically focused intense charged particle beams. This research will support the U. S. program to construct advanced accelerators for such applications as nuclear waste treatment, heavy ion fusion and free electron lasers. Research will explore self-field-induced nonlinear resonant and chaotic phenomena in intense charged particle beams.

RELATIVISTIC ELECTRONICS DIVISION

This section, led by Prof. George Bekefi, is involved in exploring the physics of novel lasers using relativistic electron beams as the lasing medium.

Free electron laser research in this division spans wavelengths ranging from millimeters to nanometers. At millimeter wavelengths (8.6 mm) we are generating 60MW of coherent radiation, the world's largest power at that wavelength. This device is now being actively used in a collaborative effort with CERN/CLIC in testing novel high gradient RF accelerating structures. The goal is to achieve accelerating gradients in excess of 100 MeV per meter length (the SLAC RF Linac achieves about 17 MeV/m). Since these systems are physically small, such gradients could in principle be achieved with minimal expenditure of RF energy.

At the opposite end of the wavelength spectrum, we are aiming at generating tens of kilowatts of coherent radiation in the X-ray regime for use in medical and biological studies. To this purpose we have designed, built and tested a novel 70 period magnetic microwiggler of 8.8 mm periodicity with unprecedented uniformity ([[ordfeminine]] 0.04%). At this level of precision, wiggler errors are sufficiently small to allow operation at X-ray wavelengths. This program is a collaboration with the Brookhaven National Laboratory where the MIT wiggler is being installed on the 80 MeV, Advanced Test Facility, RF Linac. Radiation at a wavelength of 250 nm is expected within 12 months. Achievement of this goal would be the first of its kind in which an X-ray free electron laser is being driven by a linear RF accelerator.

AFFIRMATIVE ACTION

The Plasma Fusion Center is committed to increasing the number of women and minorities at those levels of the work force where there is significant under representation. Our success in meeting this objective is dependent on the pool of applicants available at each level. For example, 75% of both the SRS administrative and support staff are women, while 25% are African Americans. In these categories, we have found that our search procedures, which utilize both internal and external resources, have turned up an excellent supply of highly qualified candidates. On the other hand, at the SRS technical level our success is more modest: approximately 3.1% of SRS technical staff are women, while 14.6% are other minorities, most of whom are Asian Americans. We are attempting to enlarge the reservoir of qualified underrepresented applicants in the near term by more intensive dissemination of job postings to organizations specifically concerned with opportunities for women and other minorities and, in the long term, with a substantial K-12 and undergraduate outreach effort which encourages women and other minorities to pursue careers as scientists and engineers.

EDUCATIONAL OUTREACH PROGRAMS

The Plasma Fusion Center has established an educational outreach program primarily focused on heightening the interest of K-12 students in scientific and technical subjects. The Mr. Magnet Program, headed by Technical Supervisor Paul Thomas, has been particularly successful. Mr. Magnet, with the help of a graduate student, brings a traveling demonstration on magnetism into local elementary schools, inspiring and exciting students with the chance to take part in hands-on experiments with magnets. He stresses that science is a valid pursuit for boys and girls. Over the past year he has worked with over 10,000 students. The PFC also seeks to educate 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 PFC for a day of hands-on demonstrations and tours.

The PFC has also become involved in the Contemporary Physics Education Project (CPEP), a collaborative effort of fusion facilities around the U.S. The goal of this group is to create a fusion-oriented curriculum, along with supporting hands-on experiments and graphics, for use in high schools around the country. Mr. Paul Rivenberg has worked on the "Chart Committee" of this project, which is focusing on creating wall charts that will aid in the understanding of fusion.

FUSION FORUM DAYS IN CONGRESS

The Fusion Forum, held each year on Capitol Hill, is a community-wide effort to show Congress the goals of the national fusion program and its gains over the past year. Fusion fundamentals are also outlined to educate new Congressmen and staff members. In March 1995 Miklos Porkolab, Bruce Montgomery, Dan Cohn and Albe Dawson, together with Tobin Smith of the MIT Washington office participated in the Forum. An exhibit was brought to Washington to show our 1) education and educational outreach programs, 2) Alcator C-Mod and ITER magnetics accomplishments and 3) the PFC's plasma-science-based spin-off technologies including hazardous waste remediation, microchip manufacture, and cutting tool plasma-spray coatings to increase surface hardness and tool life up to 100-fold at a very small cost increase. A videotape showing plasmas in C-Mod received considerable attention. Bruce Montgomery testified before the House Appropriations Subcommittee on Energy and Water, and Miklos Porkolab and Dan Cohn made visits to several members of the Massachusetts congressional delegation to garner their support for the fusion program. The exhibit was selected to remain on display in the Cannon House Office building for the two weeks following the Forum. Attendance was considerably higher than in previous years.

APPOINTMENTS AND PROMOTIONS

During the past year, there have been several important appointments and promotions in Plasma Fusion Center program areas:

Appointments include: Vincent Bertolino (Sullivan and Cogliano) appointed Systems Engineer in the Alcator C-Mod Division; Changheui Jang (MIT, Nuclear Engineer) appointed Postdoctoral Research Staff and Philip Michael (Yokohama National University) appointed Research Engineer in the Fusion Technology and Engineering Division; Eileen Ng (Artificial Intelligence Lab) appointed Assistant Fiscal Officer in the Fiscal Office; Rosaria Rizzo (Earth Atmospheric and Planetary Sciences) appointed Assistant Fiscal Officer in the Fiscal Office; Willie Smith (Provost's Office) appointed Administrative Officer; Robert Vibert (National Magnet Lab) appointed Assistant Fiscal Officer in the Fiscal Office; and Randy West (Diversified Technologies Inc.) appointed Engineer-Temporary in the Fusion Technology and Engineering Division.

Internal promotions in the Plasma Fusion Center during the past year include: Veronica DuLong, promoted to Associate Fiscal Officer in the Fiscal Office; Chenyu Gung, promoted to Research Engineer in the Fusion Technology and Engineering Division; Kamal Hadidi, promoted to Research Scientist in the Plasma Technology and Systems Division; James Irby, promoted to Head of Operations Section of the Alcator C-Mod Division; and Pei-Wen Wang, promoted to Research Engineer in the Fusion Technology and Engineering Division.

During the past year, there was one Institute research promotion in the Plasma Fusion Center: Prof. Miklos Porkolab, promoted to PFC Director.

The Plasma Fusion Center has also hosted 68 Visiting Scientists, Engineers and Scholars during the past year.

GRADUATE DEGREES

During the past year, the following students graduated with theses in plasma fusion and related areas: Monica Blank, Ph.D., Electrical Engineering and Computer Science; Adam Brailove, Ph.D., Physics; Michael Graf, Ph.D., Nuclear Engineering; Carsie Hall II, M.S., Mechanical Engineering; Christian Kurz, Ph.D., Nuclear Engineering; Chia-Liang Lin, Ph.D., Electrical Engineering and Computer Science; Thomas Luke, Ph.D., Physics; Martin Morra, Ph.D., Material Science and Engineering; Gennady Shvets, Ph.D., Physics; Jesus Villasenor, Ph.D., Physics; and Ali Zolfaghari, Ph.D., Nuclear Engineering. We take this opportunity to wish these graduates success in their future professional endeavors.

Miklos Porkolab

MIT Reports to the President 1994-95