Determination of the Kelvin-Helmholtz Wave Parameters on the Magnetopause in Single-spacecraft Observations
doi: 10.11728/cjss2014.04.403
Determination of the Kelvin-Helmholtz Wave Parameters on the Magnetopause in Single-spacecraft Observations
-
摘要: Kelvin-Helmholtz (K-H) waves are formed from the triggeringof the K-H instability on the magnetopause, which is a candidatemechanism for solar wind entry into the magnetosphere, especially undernorthward interplanetary magnetic field conditions. In this study, aK-H wave event was identified from the observation of probe Bof the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission on 15 May 2008. A new method to determinethe wave parameters of the K-H waves in single-spacecraft observationsis proposed. The dominant wave period is determined by three kinds ofspectrograms for three key parameters, namely the ion density, the iontemperature, and the z component of magnetic field. The phasevelocity is estimated by calculating the center-of-mass velocity of thedetected K-H vortex region. This approximation is validated bycomparison with other alternative methods. The method to determine thewave parameters is a first step to further study K-H wave properties and their relationship with interplanetaryconditions.Abstract: Kelvin-Helmholtz (K-H) waves are formed from the triggeringof the K-H instability on the magnetopause, which is a candidatemechanism for solar wind entry into the magnetosphere, especially undernorthward interplanetary magnetic field conditions. In this study, aK-H wave event was identified from the observation of probe Bof the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission on 15 May 2008. A new method to determinethe wave parameters of the K-H waves in single-spacecraft observationsis proposed. The dominant wave period is determined by three kinds ofspectrograms for three key parameters, namely the ion density, the iontemperature, and the z component of magnetic field. The phasevelocity is estimated by calculating the center-of-mass velocity of thedetected K-H vortex region. This approximation is validated bycomparison with other alternative methods. The method to determine thewave parameters is a first step to further study K-H wave properties and their relationship with interplanetaryconditions.
-
Key words:
- Kelvin-Helmholtz waves /
- Magnetopause /
- Single-spacecraft observation
-
[1] Wang C, Belcher J W. Numerical investigation of hydrodynamic instabilities of the heliopause [J]. J. Geophys. Res., 1998, 103(A1):247-256 [2] Southwood D J. The hydromagnetic stability of the magnetospheric boundary [J]. Planet. Space Sci., 1968, 16(5):587-605 [3] Miura A. Anomalous transport by magnetohydrodynamic Kelvin-Helmholtz instabilities in the solar windmagnetosphere interaction [J]. J. Geophys. Res., 1984, 89(A2):801-818 [4] Hasegawa H, Fujimoto M, Phan T D, et al. Transport of solar wind into Earth’s magnetosphere through rolled-up Kelvin-Helmholtz vortices [J]. Nature, 2004, 430(7001):755-758 [5] Mitchell D G, Kutchko F, Williams D J, et al. An extended study of the low-latitude boundary layer on the dawn and dusk flanks of the magnetosphere [J]. J. Geophys. Res., 1987, 92(A7):7394-7404 [6] Terasawa T, Fujimoto M, Mukai T, et al. Solar wind control of density and temperature in the near-Earth plasma sheet: Wind/Geotail collaboration [J]. Geophys. Res. Lett., 1997, 24(8):935-938 [7] Wang Chi. MHD simulations on the interaction of the solar wind with the magnetosphere [J]. Chin. J. Space Sci., 2011, 31(4):413-428 [8] Guo X C, Wang C, Hu Y Q. Global MHD simulation of the Kelvin-Helmholtz instability at the magnetopause for northward interplanetary magnetic field [J]. J. Geophys. Res., 2010, 115(A10):218 [9] LiW Y, Guo X C,Wang C. Spatial distribution of Kelvin- Helmholtz instability at low-latitude boundary layer under different solar wind speed conditions [J]. J. Geophys. Res., 2012, 117(A8):230 [10] Takagi K, Hashimoto C, Hasegawa H, et al. Kelvin- Helmholtz instability in a magnetotail flank-like geometry: Three-dimensional MHD simulations [J]. J. Geophys. Res., 2006, 111(A8):202 [11] Hasegawa H, Fujimoto M, Takagi K, et al. Singlespacecraft detection of rolled-up Kelvin-Helmholtz vortices at the flank magnetopause [J]. J. Geophys. Res., 2006, 111(A9):203 [12] Taylor M G G T, Hasegawa H, Lavraud B, et al. Spatial distribution of rolled up Kelvin-Helmholtz vortices at Earth’s dayside and flank magnetopause [J]. Ann. Geophys., 2012, 30(6):1025-1035 [13] Angelopoulos V. The THEMIS mission. New York: Springer, 2008:534 [14] Shue J H, Chao J K, Fu H C, et al. A new functional form to study the solar wind control of the magnetopause size and shape [J]. J. Geophys. Res., 1997, 102(A5):9497-9511 [15] Foullon C, Farrugia C J, Fazakerley A N, et al. Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause[J]. J. Geophys. Res., 2008, 113(A11):203 [16] Chandrasekhar S. Hydrodynamic and Hydromagnetic Stability [M]. New York: Oxford University Press, 1961 [17] Hasegawa H, Retino A, Vaivads A, et al. Kelvin-Helmholtz waves at the Earth’s magnetopause: Multiscale development and associated reconnection [J]. J. Geophys. Res., 2009, 114(A12):207 [18] Hasegawa H. Comment on Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause [J]. J. Geophys. Res., 2009, 114(A3):205
点击查看大图
计量
- 文章访问数: 918
- HTML全文浏览量: 33
- PDF下载量: 1484
- 被引次数: 0