COMMENTS ON LECTURE - CIRCULAR POLARIZATION - OCTOBER 30, 2002

	When Bolek indicated that his identification of the presented
	wave as right-hand circularly-polarized (RHCP), his usage was
	indeed consistent with the use in B&B.  B&B admit that their
	usage is not universal (because it's not), but it at least
	agrees with what was done in recitation this morning.

	In Bolek's presentation, he had a total of four uses of signs
	that are not the same as in the text, but which overall give
	the same result.  In order:

	    (a)  In Equations (3.83, (3.84) and (3.85), switch the
	    signs on both the "omega*t" and "k*z" terms.

	    (b)  This means that Bolek's phi is the text's phi_y-phi_x

	    (c)  Hence, Bolek had a CLOCKWISE rotation.

	    (d)  The kicker:  Bolek had the z-axis pointing INTO the
	    board, and clockwise with the direction of propagation
	    into the board counts as RHCP.

	The text gets into "(One way to remember this ...)"  The
	reason there is any disagreement at all in the convention is
	that the wave propagates in space but we considered fixing
	space and seeing what happens when time changes.  To see why
	this makes a difference, find a Slinky.  (I have three, one
	with a different orientation.)  Stretch the Slinky, and see
	which way the material rotates when you move spatially along
	the axis.  Then, stay at one point and move the Slinky;  the
	rotation is in the other direction!  Don't believe me, do it.