July 27, 2015 to August 21, 2015
Nordita, Stockholm
Europe/Stockholm timezone

Conversion of electromagnetic energy at plasma jet fronts

Aug 11, 2015, 4:10 PM
15m
FD5 (Nordita, Stockholm)

FD5

Nordita, Stockholm

Oral Workshop, August 10-14 Afternoon II

Speaker

Dr Yuri Khotyaintsev (Swedish Institute of Space Physics)

Description

We use multi-spacecraft observations by Cluster and MMS in the magnetotail and 3D PIC simulations to investigate conversion of electromagnetic energy at the front of a fast plasma jet. Such plasma jet can be produced as a result of magnetic reconnection. Jet fronts are known to have a sharp increase of magnetic field (referred to as dipolarization fronts in the magnetospheric physics) as well as sharp gradients in plasma density and temperature. These sharp gradients at the front generate broadband turbulence in the lower-hybrid frequency range, which have amplitudes several times larger than the convective field, wave potential comparable to electron thermal energy, and perpendicular wavelength of the order of several electron gyro-scales. Despite the large wave amplitudes, we find only moderate dissipation due to these waves in the front reference frame, which goes into heating of electrons. We find that the major dissipation is happening in the Earth (laboratory) frame and it is related to reflection and acceleration of ions from the jet front. This dissipation operates at scales of the order several ion inertial lengths, and the primary contribution to E*J is coming from the convective electric field of the front (E=Vfront_x B) and the current flowing at the front.

Primary author

Dr Yuri Khotyaintsev (Swedish Institute of Space Physics)

Co-authors

Dr Alessandro Retinó (Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, France) Dr Andrey Divin (Saint Petersburg State University, Russia) Dr Andris Vaivads (Swedish Institute of Space Physics) Prof. Christopher C. Russell (University of California, Los Angeles, CA, USA) Prof. Mats André (Swedish Institute of Space Physics) Dr Olivier Le Contel (Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, France) Dr Per-Arne Lindqvist (Royal Institute of Technology, Stockholm, Sweden) Prof. Robert R. Ergun (University of Colorado, Boulder, CO, USA) Prof. Roy Torbert (University of New Hampshire, Durham, NH, USA) Dr Werner Magnes (Space Research Institute, Austrian Academy of Sciences, Graz, Austria)

Presentation materials