HR: 08:35h
AN: SM21A-03 INVITED [PDF]
TI: Dispersive Alfv\'{e}n Waves: Lab Verification of Theory for Inertial, Kinetic, and
In-between
AU: * Kletzing, C A
EM: craig-kletzing@uiowa.edu
AF: Department of Physics \& Astronomy, 203 Van Allen Hall,
The University of Iowa, Iowa City, IA 52242 United States
AU: Bounds, S R
EM: scott-bounds@uiowa.edu
AF: Department of Physics \& Astronomy, 203 Van Allen Hall,
The University of Iowa, Iowa City, IA 52242 United States
AU: Skiff, F
EM: frederick-skiff@uiowa.edu
AF: Department of Physics \& Astronomy, 203 Van Allen Hall,
The University of Iowa, Iowa City, IA 52242 United States
AU: Gekelman, W
EM: gekelman@physics.ucla.edu
AF: Department of Physics \& Astronomy, University of California, Los Angeles,
1000 Veterans Aven, Suite 15-70, Los Angeles, CA 90095-1696 United States
AU: Vincena, S
EM: vincena@physics.ucla.edu
AF: Department of Physics \& Astronomy, University of California, Los Angeles,
1000 Veterans Aven, Suite 15-70, Los Angeles, CA 90095-1696 United States
AB:
Shear Alfv\'{e}n waves are thought to play a significant role in several regions of near-Earth space including the plasma
sheet, magnetopause, and auroral zone. The interesting physics occurs when the waves have narrow perpendicular structure such
that the perpendicular scale is of the order of the ion acoustic gyroradius or the electron skin depth. Despite the
importance of these waves, there are few experimental tests of the basic theory of these wave for conditions for which finite
$k_\perp$ is important. We present the results of a series of laboratory, measurements of the shear Alfv\'{e}n wave
dispersion relation for waves in the inertial ($V_{th} \ll V_A$) and kinetic regimes ($V_{th} \gg V_A$)as well as for when
the waves are in-between ($V_{th} \approx V_A$). The measurements were performed at the LArge Plasm Device at UCLA using the
University of Iowa Arbitrary Spatial Waveform antenna. This antenna allows us to probe the dispersive nature of these waves
for non-negligible $k_\perp$. Examples of the kinds of waveforms which can be generated are shown to demonstrate the
flexibility of the system. By comparing the arrival times of the waves at spatially separated points, the wave phase velocity
is determined which is then compared to the theoretical dispersion relation. The dispersion relation shows the expected
response in parallel phase velocity with increasing perpendicular wave number. We compare two-fluid and kinetic descriptions
of the dispersion and find that the best agreement between theory and experiment occurs for the warm plasma dispersion
relation including collisional damping.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2471 Plasma waves and instabilities
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2772 Plasma waves and instabilities
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting