title: Collisionless coupling of ion and electron temperatures in counterstreaming plasma flows.
abstract: Rapid electron and ion heating is observed in collisionless counterstreaming plasma flows and explained via a novel heating mechanism that couples the electron and ion temperatures. Recent experiments measure plasma conditions 4 mm from the surface of single foil (single plasma stream) and double foils (two counterstreaming plasmas) targets using Thomson scattering. Significant increases in electron and ion temperatures (from <100 eV to >1 keV) compared to the single foil geometry are observed. While electrons are heated by friction on opposite going ions, ion-ion collisions cannot explain the observed ion heating. Also, density and flow velocity measurements show negligible slow down and rule out stagnation. The nonlinear saturation of an acoustic two-stream electrostatic instability is predicted to couple the ion temperature to the electron temperature through the dynamic evolution of the instability threshold. Particle-in-cell simulations including both collisional and collisionless effects are compared to the experimental measurements and show rapid electron and ion heating consistent with the experimental measurements.
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Ross
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: H-S
authors.initials: HS
authors.lastname: Park
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: R
authors.initials: R
authors.lastname: Berger
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: L
authors.initials: L
authors.lastname: Divol
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: N L
authors.initials: NL
authors.lastname: Kugland
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA and Department of Physics, University of Alberta Edmonton, Alberta, Canada T6G 2R3.
authors.forename: W
authors.initials: W
authors.lastname: Rozmus
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: D
authors.initials: D
authors.lastname: Ryutov
authors.affiliation: Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Glenzer