進階搜尋


下載電子全文  
系統識別號 U0026-3107201315210800
論文名稱(中文) 模擬離子環狀速度分佈之形成
論文名稱(英文) Simulation of the Formation of the Ion Ring Velocity Distributions
校院名稱 成功大學
系所名稱(中) 太空天文與電漿科學研究所
系所名稱(英) Assistant, Institute of Space, Astrophysical and Plasma Sciences(ISAPS)
學年度 101
學期 2
出版年 102
研究生(中文) 林協成
研究生(英文) Hsieh-Cheng Lin
學號 LA6991015
學位類別 碩士
語文別 英文
論文頁數 46頁
口試委員 指導教授-談永頤
口試委員-汪愷悌
口試委員-西村泰太郎
口試委員-許志浤
中文關鍵字 離子環狀速度分佈 
英文關鍵字 Ion Ring Velocity Distribution 
學科別分類
中文摘要 離子環狀速度分佈通常在范艾倫輻射帶中靠近磁赤道黃昏側被觀測到。這篇研究論文嘗試去探討來源於磁尾且飄移到范艾倫輻射帶的離子是否為形成離子環狀速度分佈的原因;因為磁矩守恆,所以當這些從磁尾漂移來的離子越來越靠近地球,垂直磁場的速度也越來越增加。當離子的垂直磁場速度比當地的漂移速度高的時候,在垂直磁場平面上的漂移行為就不如迴旋運動重要。迴旋運動的相位變化可能會引起環狀速度分佈。
為了模擬離子的運動,本研究結合了Tsyganenko(T01) 和地球偶極磁場模型,且根據太陽風資料,加入一個晨昏方向之電場。在此模擬中,我們在范艾倫輻射帶靠近磁赤道黃昏側放置一個觀測地點,並紀錄帶正電氫離子通過該地點時的速度。理論上,為了強調迴旋相位的重要性,在初始條件裡我們在每一組平行及垂直速度使用20顆不同相速度的離子,從磁尾的特定區域追蹤氫離子的運動行為。模擬結果顯示在觀測地點的離子其垂直於磁場的速度分佈會組成一個環的形狀。另一方面,我們也採用連續方程式的概念來計算從磁尾特定區域的離子到達觀測地點的密度貢獻。
英文摘要 Ion ring velocity distributions are commonly observed near the magnetic equator in the evening side of the radiation belts. In this study, we would like to explore magnetotail ions as a source of the ion ring velocity distributions due to their drift from the magnetotail to the radiation belts; these ions have increasing velocity perpendicular to the magnetic field velocity perpendicular to the magnetic field as they drift toward the Earth because their magnetic moment is an invariant. When their perpendicular velocity is significantly larger than their local drift velocity, the majority of their perpendicular motion goes into gyration rather than drift. The variation of their gyration phase may give rise to the ring velocity distribution.
In our simulations of the ion’s motions, we combine the Tsyganenko model T01 with the dipole field model to form the magnetic field, and impose a dawn-to-dusk electric field based on solar wind observations. We set an observation site near the magnetic equator in the evening side of the radiation belts to record the velocities of H+ ions that reach there. To emphasize the importance of the gyration phase in the theory, we use 20 different ions with different gyration phases to represent any given pair of parallel and perpendicular velocities in the initial conditions of the particle simulations. By tracking the motions of H+ ions from a specific source region in the magnetotail, we show that their perpendicular velocities at the observation site of our simulations constitute the form of a ring in the velocity distribution. Using the idea of continuity, we discuss how to calculate the density contribution at the observation site due to the ions from the magnetotail source.
論文目次 CONTENTS
ABSTRACT II
LIST OF FIGURES V
1. INTRODUCTION 1
2. Mathematical Methods & Analysis Procedure 3
2.1 Magnetic Field Model 3
2.2 Fourth-Order Runge-Kutta Method 5
2.3 Unit Integration, Time Step and Coordinate Transformation 7
3. Simulations with an Arbitrary Magnetotail Source Location 10
4. Simulations Back In Time from Observation Site to the Magnetotail 15
5. Simulations of Ion from The Magnetotail to the Observation Site (0,5,0) 19
6. Summary and Future Work 37
Reference 38
Appendix 1 40
Appendix 2 45
















LIST OF FIGURES
Figure 1.1 Ion ring velocity distribution observed by the GEOS satellite 2
Figure 2.1 Earth’s field lines generated by the Tsyganenko T01 model 5
Figure 2.2 Illustration of the idea of the Fouth-order Runge-Kutta method 6
Figure 3.1 A test H+ ion particle trajectory in x-y-z three-dimensional space 10
Figure 3.2 A test H+ ion trajectory in the two-dimensional x-y space 11
Figure 3.3 Twenty H+ ion trajectories in the x-y-z space 13
Figure 3.4 Twenty H+ ion trajectories in the x-y space 14
Figure 4.1 The scattered plot of the locations of the H+ ions in the R=15RE plane when traced back from the observation site (0,5,0). The color indicates the speed of the ions 17
Figure 4.2 The counts of the distribution of the R=15RE plane, which is divided into 2。by 2。 in the plane 18
Figure 5.1 Schematic diagram of one of the 20 H+ ions a gyroradius rL away from the guiding center in double-primed coordinates 20
Figure 5.2 Illustration of the relationship between the locations and velocities of an ion and its guiding center in double-primed coordinates 24
Figure 5.3 Scattered plot of the three-dimensional velocities of the H+ ions in double-primed coordinates, as observed at the simulation observation point 29
Figure 5.4 Scattered plots of the velocities of the H+ ions projected onto the plane as observed at the simulation observation point 30
Figure 5.5 The counts in each grid of the two dimensional velocities ( ) of the observed H+ ions 31
Figure 5.6 Demonstrate the four ion particles around the observed particles at the magnetotail 33
Figure 5.7 Two possible ways of forming the cross section for A2 34
Figure 5.8 Scattered plot the two-dimensional velocities of the observed H+ ions in double-primed coordinates, with the color indicating the amount of density n2 carried by each ion 35
Figure 5.9 The total n2 in each grid of the two-dimensional velocity distributions of the observed H+ ions in double-primed coordinates 36
Figure A1.1 Coordinate transformations from GSM to double prime. Dotted blue lines are the projection of the magnetic field vector onto the x-y plane, and the z-component of the magnetic field vector 40
Figure A1.2 Illustration of coordinate transformation processing from a three-dimensional point of view 41
Figure A1.3 Coordinate transformation from (x,y,z) to ( ) as viewed from the z-axis: fix the z-axis and rotate in the x-y plane 42
Figure A1.4 Coordinate transformation from ( ) to ( ) as viewed from the : fix the and rotate in the x-y plane 43
Figure A2.1 Wall of the tube is formed by the trajectories of the ions initially around point 1 45
參考文獻 Akasofu, S.-I., Interplanetary energy flux associated with magnetospheric substorms, Planet. Space Sci., 27, 425-431, 1979.

Andre´, R., F. Lefeuvre, F. Simonet, and U. S. Inan, A first approach to model the low-frequency wave activity in the plasmasphere, Ann. Geophys., 20, 981– 996, 2002.

Chen, R.-L., Case Studies on Equatorial Emissions in the Inner Magnetosphere Using THEMIS Observations, Master thesis, National Cheng Kung University, 2011.

Fok, M. C., T. E. Moore, J. U. Kozyra, G. C. Ho, and D. C. Hamilton, Three-dimensional ring current decay model, J. Geophys. Res., 100, 9619-9632, 1995.

Fok, M. C., T. E. Moore, and M. E. Greenspan, Ring current development during storm main phase, J. Geophys. Res., 101, 15,311-15,322, 1996.

Horne, R. B., R. M. Thorne, S. A. Glauert, N. P. Meredith, D. Pokhotelov, and O. Santolıik, Electron acceleration in the Van Allen radiation belts by fast magnetosonic waves, Geophys. Res. Lett., 34, L17107, DOI: 10.1029/2007GL030267, 2007.
Jordanova, V. K., L. M. Kistler, J. U. Kozyra, G. V. Khazanov, and A. F. Nagy, Collisional loss of ring current ions, J. Geophys. Res., 101, 111, 1996.

Jordanova, V. K., C. J. Farrugia, J. M. Quinn, R. B. Torbert, J. E. Borovsky, R. B. Sheldon, and W. K. Peterson, Simulations of off-equatorial ring current ion spectra measured by Polar for a moderate storm at solar minimum, J. Geophys. Res., 104, 429-436, 1999.

Lennartsson, W., R. D. Sharp, E. G. Shelley, R. G. Johnson, and H. Balsiger, Ion composition and energy distribution during 10 magnetic storms, J. Geophys. Res., 86, 4628– 4638, 1981.

McClements, K. G., J. J. Su, R. Bingham, J. M. Dawson, D. S. Spicer, Simulation studies of electron acceleration by ion ring distributions in solar flares, Solar Physics 130, 229-241, 1990.

Perraut, S., A. Roux, P. Robert, R. Gendrin, J. A. Sauvaud, J. M. Bosqued, G. Kremser, and A. Korth, A systematic study of ULF waves above FH+ from GEOS 1 and 2 measurements and their relationships with proton ring distributions, J. Geophys. Res., 87, 6219-6236, DOI:10.1029/JA087iA08p06219, 1982.

Russell, C. T., R. E. Holzer, E. J. Smith, OGO 3 observations of ELF noise in the magnetosphere, Space Sci, 75, 4, DOI: 10.1029/JA074i003p00755, 1970.
Tsyganenko, N. A., Solar wind control of the tail lobe magnetic field as deduced from Geotail, AMPTE/IRM, and ISEE-2 data, J. Geophys. Res., 105, 5517-5528, 2000.

Tsyganenko, N. A., A model of the near magnetosphere with a dawn-dusk asymmetry, 1, Mathematical structure, J. Geophys. Res., 107, DOI:10.1029/2001JA000219, 2002a.

Tsyganenko, N. A., A model of the near magnetosphere with a dawn-dusk asymmetry, 2, Parameterization and fitting to observations, J. Geophys. Res., 107, DOI:10.1029/2001JA000220, 2002b.
論文全文使用權限
  • 同意授權校內瀏覽/列印電子全文服務,於2018-08-05起公開。
  • 同意授權校外瀏覽/列印電子全文服務,於2018-08-05起公開。


  • 如您有疑問,請聯絡圖書館
    聯絡電話:(06)2757575#65773
    聯絡E-mail:etds@email.ncku.edu.tw