Linear Instability and Saturation Characteristics of Magnetosonic Waves along the Magnetic Field Line

Min, Kyungguk1; Liu, Kaijun2

2020-06

10.5140/JASS.2020.37.2.85

Journal of Astronomy and Space Sciences   影响因子和分区

2093-5587

2093-1409

Equatorial noise, also known magnetosonic waves (MSWs), are one of the frequently observed plasma waves in Earth's inner magnetosphere. Observations have shown that wave amplitudes maximize at the magnetic equator with a narrow extent in their latitudinal distribution. It has been understood that waves are generated from an equatorial source region and confined within a few degrees magnetic latitude. The present study investigates whether the MSW instability and saturation amplitudes maximize at the equator, given an energetic proton ring-like distribution derived from an observed wave event, and using linear instability analysis and particle-in-cell simulations with the plasma conditions at different latitudes along the dipole magnetic field line. The results show that waves initially grow fastest (i.e., with the largest growth rate) at high latitude (20 degrees-25 degrees), but consistent with observations, their saturation amplitudes maximize within +/- 10 degrees latitude. On the other hand, the slope of the saturation amplitudes versus latitude revealed in the present study is not as steep as what the previous statistical observation results suggest. This may be indicative of some other factors not considered in the present analyses at play, such as background magnetic field and plasma inhomogeneities and the propagation effect.

equatorial noise magnetosonic waves plasma instabilities linear theory analysis particle-in-cell simulations

ESCI

英语

其他

National Natural Science Foundation of China (NSFC)[41974168] ; Korea Institute of Science and Technology Information[KSC-2019-CRE-0003]

Astronomy & Astrophysics

Astronomy & Astrophysics

WOS:000541845500002

KOREAN SPACE SCIENCE SOC

Web of Science

1.Chungnam Natl Univ, Dept Astron & Space Sci, Daejeon 34134, South Korea
2.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen, Peoples R China

Min, Kyungguk,Liu, Kaijun. Linear Instability and Saturation Characteristics of Magnetosonic Waves along the Magnetic Field Line[J]. Journal of Astronomy and Space Sciences,2020,37(2):85-94.

Min, Kyungguk,&Liu, Kaijun.(2020).Linear Instability and Saturation Characteristics of Magnetosonic Waves along the Magnetic Field Line.Journal of Astronomy and Space Sciences,37(2),85-94.

Min, Kyungguk,et al."Linear Instability and Saturation Characteristics of Magnetosonic Waves along the Magnetic Field Line".Journal of Astronomy and Space Sciences 37.2(2020):85-94.