title: Generation of a purely electrostatic collisionless shock during the expansion of a dense plasma through a rarefied medium.
abstract: A two-dimensional numerical study of the expansion of a dense plasma through a more rarefied one is reported. The electrostatic ion-acoustic shock, which is generated during the expansion, accelerates the electrons of the rarefied plasma inducing a superthermal population which reduces electron thermal anisotropy. The Weibel instability is therefore not triggered and no self-generated magnetic fields are observed, in contrast with published theoretical results dealing with plasma expansion into vacuum. The shock front develops a filamentary structure which is interpreted as the consequence of the electrostatic ion-ion instability, consistently with published analytical models and experimental results.
authors.affiliation: Centre for Plasma Physics, The Queens University of Belfast, Belfast BT7 1NN, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Sarri
authors.forename: M E
authors.initials: ME
authors.lastname: Dieckmann
authors.forename: I
authors.initials: I
authors.lastname: Kourakis
authors.forename: M
authors.initials: M
authors.lastname: Borghesi