Oblique Electromagnetic Instabilities Driven by Pickup Ion Ring-beam Distributions in the Outer Heliosheath. I. Linear Instability Analysis

Ameneh,Mousavi; Kaijun,Liu; Sina,Sadeghzadeh

2022-11-01

10.3847/1538-4357/ac9a44

ASTROPHYSICAL JOURNAL   Impact Factor & Quartile

0004-637X

1538-4357

The energetic neutral atom ribbon observed by the Interstellar Boundary Explorer spacecraft is believed to originate from the pickup ions in the outer heliosheath. The outer heliosheath pickup ions generally have a ring-beam velocity distribution at a certain pickup angle, alpha, the angle at which these ions are picked up by the interstellar magnetic field. The pickup ion ring-beam distributions can drive unstable waves of different propagation angles with respect to the background interstellar magnetic field, theta. Previous studies of the outer heliosheath pickup ion dynamics were mainly focused on ring-like pickup ion distributions with alpha approximate to 90 degrees and/or the parallel- and antiparallel-propagating unstable waves (theta = 0 degrees and 180 degrees). The present study carries out linear kinetic instability analysis to investigate both the parallel and oblique unstable modes (0 degrees <= theta <= 180 degrees) driven by ring-beam pickup ion distributions of different pickup angles between 0 degrees and 90 degrees. Our linear instability analysis reveals that ring-beam pickup ion distributions can excite oblique mirror waves as well as parallel/quasi-parallel and oblique right- and left-helicity waves. The maximum growth rate among all the instabilities belongs to the parallel-propagating left-helicity waves at most pickup angles. Furthermore, the evolution of the unstable mirror waves by varying pickup angle indicates that as the pickup angle increases, the maximum growth rate of the mirror modes increases, while its propagation angle decreases.

SCI

English

First ; Corresponding

Strategic Priority Research Program of Chinese Academy of Sciences[XDB 41000000] ; National Natural Science Foundation of China (NSFC)["41974168","42174203"] ; Shenzhen Science and Technology Program["JCYJ20190809153407516","JCY20210324104810027"]

Astronomy & Astrophysics

Astronomy & Astrophysics

WOS:000886625800001

IOP Publishing Ltd

SPACE SCIENCE

Web of Science

Department of Earth and Space Sciences, Southern University of Science and Technology, Shenzhen, 518055, People’s Republic of China;

Ameneh,Mousavi,Kaijun,Liu,Sina,Sadeghzadeh. Oblique Electromagnetic Instabilities Driven by Pickup Ion Ring-beam Distributions in the Outer Heliosheath. I. Linear Instability Analysis[J]. ASTROPHYSICAL JOURNAL,2022,940(1):36.

Ameneh,Mousavi,Kaijun,Liu,&Sina,Sadeghzadeh.(2022).Oblique Electromagnetic Instabilities Driven by Pickup Ion Ring-beam Distributions in the Outer Heliosheath. I. Linear Instability Analysis.ASTROPHYSICAL JOURNAL,940(1),36.

Ameneh,Mousavi,et al."Oblique Electromagnetic Instabilities Driven by Pickup Ion Ring-beam Distributions in the Outer Heliosheath. I. Linear Instability Analysis".ASTROPHYSICAL JOURNAL 940.1(2022):36.