HR: 0830h
AN: SH21B-0109    [PDF]
TI: Kinetic Alfv\'en Waves: Linear theory and a Particle-in-cell Simulation
AU: * Gary, S P
EM: pgary@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AU: Nishimura, K
EM: kazumi@lanl.gov
AF: Los Alamos National Laboratory, Mail Stop D466, Los Alamos, NM 87545 United States
AB: An Alfv\'en-cyclotron fluctuation of sufficiently short wavelength has a strong proton cyclotron resonance at propagation parallel to the background magnetic field ${\bf B}_o$ in a collisionless electron-proton plasma. As $\theta$, the angle between the fluctuation wavevector {\bf k} and ${\bf B}_o$ increases, proton cyclotron wave-particle interactions become weaker and the electron Landau resonance becomes effective. Define the critical angle $\theta_o$ beyond which the proton cyclotron interaction becomes nonresonant. Here linear Vlasov theory shows that this critical angle is relatively independent of $\beta_p$ over 0.001 $\le \beta_p \le$ 0.10, but that $\theta_o$ is a sensitive function of the damping rate. Also, a particle-in-cell simulation was carried out in a magnetized, homogeneous, collisionless plasma of electrons and one ion species to study the plasma response to the initial imposition of an Alfv\'en-cyclotron wave at $\theta > \theta_o$. The computation shows strong heating of the electrons in the direction parallel to ${\bf B}_o$ and the formation of a beam in the direction of parallel wave phase propagation.
DE: 2159 Plasma waves and turbulence
DE: 2164 Solar wind plasma
DE: 7843 Numerical simulation studies
DE: 7867 Wave/particle interactions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting