A comment on "Importance of resolving the spectral support of beam-plasma instabilities in simulations" by M. Shalaby et al

Abstract

Understanding the physics of beam-plasma systems is of great importance for a large number of astrophysical systems. Recently the validity of particle-in-cell simulations of these systems has been questioned by Shalaby et al. (2017) We analyse one specific beam-plasma and its numerical simulations Kempf et al. (2016) that has been critized and prove that in fact the simulations performed fulfill the new validity criteria introduced by Shalaby et al. (2016).

After discussions with M. Shalaby et al. a revision of this paper seems appropriate. While some points of the original paper can still be discussed, we do not want to distract from the valuable contribution by our colleagues. We are currently waiting for additional simulation results, that are necessary to revise our comment