Mirror instability upstream of the termination shock (TS) and in the heliosheath

详细信息    查看全文

• 作者：Bruce T. Tsurutani^a ; ^{bruce.tsurutani@jpl.nasa.gov"" rel=""nofollow} ; Ezequiel Echer^b ; Olga P. Verkhoglyadova^a ; ^c ; Gurbax S. Lakhina^d ; F.L. Guarnieri^e
• 关键词：Mirror instability ; Pickup ions ; Heliosheath ; Magnetosheaths
• 刊名：Journal of Atmospheric and Solar-Terrestrial Physics
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：73
• 期：11-12
• 页码：1398-1404
• 全文大小：523 K

文摘

We experimentally identify mirror mode (MM) structures in the Voyager 1 heliosheath data for the first time. This is done using the magnetic field data alone. The heliosheath MM structures are found to have the following characteristics: (1) quasiperiodic spacings with a typical scale size of 57 ρ_p, (2) little or no angular changes across the structures (3° longitude and 3° latitude), and (3) a lack of sharp boundaries at the magnetic dip edges. It is demonstrated that the pickup of interstellar neutrals in the upstream region of the termination shock (TS) and quasiperpendicular TS plasma compression are the causes of MM instability during intervals when the IMF is nearly orthogonal to the solar wind flow direction. Concomitant additional injection of pickup ions (PUIs) throughout the heliosheath will lead to further MM amplification. MM structures in planetary magnetosheaths and interplanetary sheaths are discussed for comparative purposes. Multiple sources of free energy are often involved.