HR: 0830h
AN: SM41B-0565 [PDF]
TI: Generation of Alfven waves by upper hybrid waves
AU: * Van Compernolle, B
EM: bvcomper@ucla.edu
AF: Dept. Physics UCLA, 1000 Veteran Avenue, Los Angeles, CA 90095-1696 United States
AU: Gekelman, W
EM: gekelman@physics.ucla.edu
AF: Dept. Physics UCLA, 1000 Veteran Avenue, Los Angeles, CA 90095-1696 United States
AU: Pribyl, P
EM: pribyl@ucla.edu
AF: Dept. Physics UCLA, 1000 Veteran Avenue, Los Angeles, CA 90095-1696 United States
AU: Carter, T
EM: tcarter@physics.ucla.edu
AF: Dept. Physics UCLA, 1000 Veteran Avenue, Los Angeles, CA 90095-1696 United States
AB:
There is a great interest in ionospheric heating and modification as
evidenced by the HAARP facility in Alaska and a large effort in Norway, and long time effort at Arecibo.
In a series of laboratory experiments at the upgraded \textbf{LA}rge
\textbf{P}lasma \textbf{D}evice (LAPD) at UCLA we are simulating these interactions.
We launch high power microwave pulses into a strongly magnetized plasma (n $\leq 10^{12} \mbox{cm}^{-3}$,
$B_0 = 1 - 2.5$ kG, He,Ne, Dia= 50 cm, Length 17m).
The microwaves (f $\simeq$ 9 GHz) are beamed either along the magnetic field into
an axial density gradient or across the magnetic field into a radial density gradient.
The microwave power is 250 kW for 1 $\mu$s pulses. The plasma is diagnosed with high frequency rf probes,
magnetic pickup loops and fast optical cameras.
Preliminary results have shown evidence of a strong interaction, which we have tentatively identified
as a large amplitude shear Alfven wave. When the microwaves are incident at right angles to the magnetic field Alfven
waves are created at the upper hybrid resonance location which is determined by the magnetic field and local density.
Preliminary data indicate that the Alfven waves are radiated by the current systems generated by fast electrons in the
resonant region.
We will present results of experiments focussing on the magnetic interaction measured with miniature pickup loops and
on fast electron generation. Movies of the experimental data on the Alfven wave generation will be presented.
DE: 0654 Plasmas
DE: 2407 Auroral ionosphere (2704)
DE: 2471 Plasma waves and instabilities
DE: 2487 Wave propagation (6934)
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting