Non-stationarity of the quasi-perpendicular bow shock: comparison between Cluster observations and simulations

0360928 - ÚFA 2012 RIV DE eng J - Journal Article
Comisel, H. - Scholer, M. - Souček, Jan - Matsukiyo, S.
Non-stationarity of the quasi-perpendicular bow shock: comparison between Cluster observations and simulations.
Annales Geophysicae. Roč. 29, č. 2 (2011), s. 263-274. ISSN 0992-7689. E-ISSN 1432-0576
Institutional research plan: CEZ:AV0Z30420517
Keywords : bow shock * Cluster * plasma waves * shock waves
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 1.842, year: 2011
http://www.ann-geophys.net/29/263/2011/angeo-29-263-2011.pdf

We performed full particle electromagnetic simulations of a quasi-perpendicular shock with parameters corresponding to the Earth's bow shock observed by Cluster on 24 January 2001. In run 1, modified two-stream instability (MTSI) is excited by the reflected solar wind ions. The waves due to the MTSI are on the whistler mode branch and have downstream directed phase velocities in the shock frame. The Poynting flux far upstream in the foot is also directed downstream. However, in the density and magnetic field compression region of the overshoot the waves are refracted and the Poynting flux in the shock frame points upstream. The MTSI is suppressed in the low mass ratio run 2, where significant reformation (“breathing”) is observed. It is suggested that the high frequency upstream waves are due to the MTSI and are not related to a nonlinear phase standing whistler. Different profiles observed by different Cluster spacecraft are due to the non-stationary behavior on a larger time scale.
Permanent Link: http://hdl.handle.net/11104/0198367