Aspects of Linear Landau Damping in Discretized Systems

Basic linear eigenmode spectra for electrostatic Langmuir waves and drift-kinetic slab ion temperature gradient modes are examined in a series of scenarios. Collisions are modeled via a Lenard-Bernstein collision operator which fundamentally alters the linear spectrum even for infinitesimal collisionality [Ng et al., Phys. Rev. Lett. 83, 1974 (1999)]. A comparison between different discretization schemes reveals that a Hermite representation is superior for accurately resolving the spectra compared to a finite differences scheme using an equidistant velocity grid. Additionally, it is shown analytically that any even power of velocity space hyperdiffusion also produces a Case-Van Kampen spectrum which, in the limit of zero hyperdiffusivity, matches the collisionless Landau solutions.


Published in:
Physics of Plasmas, 20, 022108
Year:
2013
Publisher:
Melville, American Institute of Physics
ISSN:
1070-664X
Laboratories:
SPC
CRPP




 Record created 2013-03-07, last modified 2018-01-28

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