Particle-in-cell simulation study of a lower-hybrid shock
2016 (English)In: Physics of Plasmas, ISSN 1070-664X, E-ISSN 1089-7674, Vol. 23, no 6, 062111- p.Article in journal (Refereed) PublishedText
The expansion of a magnetized high-pressure plasma into a low-pressure ambient medium is examined with particle-in-cell simulations. The magnetic field points perpendicular to the plasmas expansion direction and binary collisions between particles are absent. The expanding plasma steepens into a quasi-electrostatic shock that is sustained by the lower-hybrid (LH) wave. The ambipolar electric field points in the expansion direction and it induces together with the background magnetic field a fast E cross B drift of electrons. The drifting electrons modify the background magnetic field, resulting in its pile-up by the LH shock. The magnetic pressure gradient force accelerates the ambient ions ahead of the LH shock, reducing the relative velocity between the ambient plasma and the LH shock to about the phase speed of the shocked LH wave, transforming the LH shock into a nonlinear LH wave. The oscillations of the electrostatic potential have a larger amplitude and wavelength in the magnetized plasma than in an unmagnetized one with otherwise identical conditions. The energy loss to the drifting electrons leads to a noticeable slowdown of the LH shock compared to that in an unmagnetized plasma. Published by AIP Publishing.
Place, publisher, year, edition, pages
AMER INST PHYSICS , 2016. Vol. 23, no 6, 062111- p.
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:liu:diva-130440DOI: 10.1063/1.4953568ISI: 000379172200017OAI: oai:DiVA.org:liu-130440DiVA: diva2:952598
Funding Agencies|EPSRC [EP/N022696/1]2016-08-152016-08-052016-09-14