Collisionless coupling of ion and electron temperatures in counterstreaming plasma flows

• Published in: Physical review letters 2013-04, Vol.110 (14), p.145005-145005, Article 145005
• Main Authors: Ross, J S, Park, H-S, Berger, R, Divol, L, Kugland, N L, Rozmus, W, Ryutov, D, Glenzer, S H
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.110.145005

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 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.