Alfven-cyclotron fluctuations : linear Vlasov theory

Conference · Thu Jan 01 04:00:00 EST 2004

DOI:https://doi.org/10.1029/2004JA010399· OSTI ID:977494

Gary, S Peter

Linear Vlasov dispersion theory for a homogeneous, isotropic, collisionless, electron-proton plasma is used to examine the damping of Alfven-cyclotron fluctuations. Fluctuations of sufficiently long wavelength are essentially undamped, but as k{sub {parallel}}, the wavevector component parallel to the background magnetic field B{sub o}, reaches a characteristic dissipation value k{sub d}, the protons become cyclotron resonant and damping begins abruptly. For proton cyclotron damping, k{sub d}c/{omega}{sub p} {approx} 1 for 10{sup -3} {approx}< {beta}{sub p} {approx}< 10{sup -1} where {beta}{sub p} {identical_to} 8{pi}n{sub p}k{sub B}T{sub p}/B{sub o}{sup 2} and {omega}{sub p}/c is the proton inertial length. At k{sub {parallel}} < k{sub d}, m{sub e}/m{sub p} < {beta}{sub e} and {beta}{sub p} {approx}< 0.10, the electron Landau resonance becomes the primary contributor to fluctuation dissipation, yielding a damping rate which scales as {omega}{sub r} {radical}{beta}{sub e}(k{perpendicular}c/{omega}{sub p}){sup 2} where {omega}{sub r} is the real frequency and k{perpendicular} is the wavevector component perpendicular to B{sub o}. Over 0.10 < {beta}{sub p} {approx}< 10 the proton Landau resonance dominates damping of these waves, although no simple analytic expression for this damping rate has been found. Analytic expressions for proton cyclotron and electron Landau damping are used in a simple model of magnetic turbulent transport to calculate the dissipation range magnetic power spectra which may result from these two types of wave-particle interactions.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 977494
• Report Number(s): LA-UR-04-1428
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
CYCLOTRONS
DAMPING
DISPERSION RELATIONS
ELECTRONS
FLUCTUATIONS
LANDAU DAMPING
MAGNETIC FIELDS
PLASMA
PROTONS
RESONANCE
SPECTRA
TRANSPORT
WAVELENGTHS