The stability of freely-propagating ion acoustic waves in 2D systems*

The stability of a freely-propagating ion acoustic wave (IAW) is a basic science problem that is made difficult by the need to resolve electron kinetic effects over a timescale that greatly exceeds the IAW period during numerical simulation. Recent results examining IAW stability using a 1D+1V Vlasov-Poisson solver indicate that instability is a fundamental property of IAWs that occurs over most if not all of the parameter space of relevance to ICF experiments [1]. We present here new results addressing the fundamental question of IAW stability across a broad range of plasma conditions in a 2D+2V system using LOKI [2,3], ranging from a regime of relatively weak to a regime of relatively strong ion kinetic effects. \\[4pt] [1] T. Chapman, S. Brunner, J. W. Banks, R. L. Berger, B. I. Cohen, and E. A. Williams, Phys. Plasmas 21, 042107 (2014).\\[0pt] [2] J. W. Banks and J. A. F. Hittinger, IEEE Trans. Plasma Sci. 38, 2198 (2010).\\[0pt] [3] J. W. Banks, R. L. Berger, S. Brunner, B. I. Cohen, and J. A. F. Hittinger, Phys. Plasmas 18, 052102 (2011).