Waves at the electron plasma frequency associated with solar wind magnetic holes: STEREO/Cluster observations

0353797 - ÚFA 2011 RIV US eng J - Journal Article
Briand, C. - Souček, Jan - Henri, P. - Mangeney, A.
Waves at the electron plasma frequency associated with solar wind magnetic holes: STEREO/Cluster observations.
Journal of Geophysical Research. Roč. 115, - (2010), A12113/1-A12113/11. ISSN 0148-0227
R&D Projects: GA ČR GP205/08/P129
Institutional research plan: CEZ:AV0Z30420517
Keywords : solar wind * Langmuir waves * magnetic holes * STEREO * CLUSTER
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 3.303, year: 2010

Magnetic depressions are common structures of the interplanetary medium. These magnetic holes can be just isolated dips of the amplitude of the field or they can be associated with discontinuities in the field orientation (tangential or rotational). Electrostatic waves at the plasma frequency (Langmuir waves) are often observed in these magnetic structures. The aim of the present paper is to provide the main characteristics of these waves and to propose a mechanism to explain their formation. The study is based on a statistical analysis of observations performed by STEREO and Cluster when each mission was in the free solar wind. We first provide new characteristics of the waves (polarization, energy, spectrum, occurrence). We then show that the occurrence of Langmuir waves activity inside a hole is closely linked to the presence of a significant electron strahl outside the hole. Finally, we propose a scenario for the generation of the Langmuir waves inside the holes.
Permanent Link: http://hdl.handle.net/11104/0192941