Analysis of the Energy Flux Density near Electron Diffusion Region of Asymmetric Magnetic Field Reconnection
-
摘要: 磁场重联是等离子体中非常重要的能量转换过程，研究该过程中的能量转化形式及其分配十分重要。目前有很多关于对称重联中的能量通量的研究，而磁层顶的非对称重联的研究却很少，特别是多事件的统计研究。因此挑选了MMS卫星观测到的10个经过电子扩散区的磁层顶重联事件对其进行分析，结果表明在不同的事件中能量通量的分配情况不一样，但在大多数事件中，离子焓通量占主导地位，其次是坡印廷通量，离子热通量略小于坡印廷通量，离子动能通量、电子焓通量和电子热通量占比在10%以下。通过对事件进行归一化处理，得到了L方向和M方向的不同能量通量随L方向的磁场和离子速度的关系图，并分析了每种能量通量的分布特征。Abstract: Magnetic reconnection is a crucial energy conversion process in plasmas, and it is important to study the forms of energy conversion and their distribution in this process. Previous research has focused mainly on the energy fluxes in symmetric reconnection, while the study of asymmetric reconnection at the Earth’s magnetopause, especially in terms of statistical analysis of multiple events, has been limited. Therefore, 10 magnetic reconnection events at the magnetopause observed by MMS satellite that passed through the electron diffusion region were used for analysis . Found that the energy flux distribution varies among different events. However, in most of the events, the ion enthalpy flux is the dominant, followed by the Poynting flux. The ion heat flux is slightly smaller than the Poynting flux, and the ion kinetic energy flux, electron enthalpy flux and electron heat flux account for less than 10% of the total energy flux. By normalizing the events, obtained the relationship diagram of different energy fluxes in the L and M directions with the magnetic field and ion velocity in the L direction, and analyze the characteristic distribution of each energy flux.
-
图 1 BURST精度下的数据（粉色线所划区域为出流区，黑色线为EDR的位置）
Figure 1. Data with BURST accuracy (Region marked by the pink lines are the outflow region, and the region near the black line is the EDR)
图 2 FAST精度下的数据（蓝色线所划区域为磁层，粉色线所划区域为磁鞘）
Figure 2. Data with FAST accuracy (Region marked by the blue lines are the magnetosphere, and the region marked by the pink lines are the magnetic sheath)
图 4 10个事件中的每种能量通量的占比情况
Figure 4. Proportions of each type of energy flux in the 10 events
图 5 10个事件中的每种能量通量LMN三个方向的分配情况
Figure 5. Distributions of energy flux in the three directions of LMN in each of the 10 events
图 6 归一化的离子L方向和M方向能量通量与BL和vi,L的关系以及每个格点的数据点数
Figure 6. Normalized L and M directions ion energy flux densities in relation to BL and vi,L and the number of data points in each cell
图 7 归一化的电子L方向和M方向的能量通量与BL和vi,L的关系图以及每个格点的数据点数
Figure 7. Normalized L and M directions electron energy flux densities in relation to BL and vi,L and the number of data points in each cell
表 1 10个事件的每种能量通量的占比情况
Table 1. Proportion of each energy flux for 10 events
事件号 发生时间（UT） vX-line/（km·s–1） Hi Ki Qi He Ke Qe S 1 2015-10-16
13:06:40－13:07:10112 0.51 0.14 0.17 0.07 <0.01 0.05 0.07 2 2015-10-22
06:04:40－06:05:4047 0.56 0.08 0.11 0.10 <0.01 0.04 0.11 3 2015-11-01
15:07:00－15:08:006 0.41 0.06 0.23 0.06 <0.01 0.05 0.20 4 2015-12-06
23:37:34－23:39:4320 0.27 0.03 0.11 0.17 <0.01 0.21 0.20 5 2015-12-08
00:05:34－00:10:1369 0.46 0.08 0.06 0.04 <0.01 0.02 0.35 6 2015-12-08
11:19:04－11:22:23180 0.33 0.03 0.16 0.06 <0.01 0.04 0.38 7 2015-12-11
11:16:24－11:18:2395 0.69 0.03 0.14 0.05 <0.01 0.03 0.06 8 2015-12-14
01:16:34－01:18:0340 0.26 0.05 0.05 0.11 <0.01 0.16 0.37 9 2016-01-10
09:11:24－09:15:53136 0.46 0.06 0.15 0.06 <0.01 0.06 0.22 10 2016-11-28
07:35:00－07:38:0018 0.30 0.03 0.32 0.02 <0.01 0.03 0.30 
下载: 导出CSV
-
[1] VASYLIUNAS V M. Theoretical models of magnetic field line merging[J]. Reviews of Geophysics, 1975, 13(1): 303-336 doi: 10.1029/RG013i001p00303 [2] YAMADA M. Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas[J]. Physics of Plasmas, 2007, 14(5): 058102 doi: 10.1063/1.2740595 [3] PASCHMANN G, ØIEROSET M, PHAN T. In-situ observations of reconnection in space[J]. Space Science Reviews, 2013, 178(2): 385-417 [4] FUSELIER S A, LEWIS W S. Properties of near-Earth magnetic reconnection from in-situ observations[J]. Space Science Reviews, 2011, 160(1): 95-121 [5] 王水, 陆全明. 无碰撞磁场重联[M]. 北京: 科学出版社, 2019WANG Shui, LU Quanming. Magnetic Reconnection[M]. Beijing: Science Press, 2019 [6] CASSAK P A, SHAY M A. Scaling of asymmetric magnetic reconnection: General theory and collisional simulations[J]. Physics of Plasmas, 2007, 14(10): 102114 doi: 10.1063/1.2795630 [7] CASSAK P A, SHAY M A. Scaling of asymmetric Hall magnetic reconnection[J]. Geophysical Research Letters, 2008, 35(19): L19102 doi: 10.1029/2008GL035268 [8] YI Y Y, ZHOU M, SONG L J, et al. On the energy conversion rate during collisionless magnetic reconnection[J]. The Astrophysical Journal Letters, 2019, 883(1): L22 doi: 10.3847/2041-8213/ab40c1 [9] ZHONG Z H, DENG X H, ZHOU M, et al. Energy conversion and dissipation at dipolarization fronts: A statistical overview[J]. Geophysical Research Letters, 2019, 46(22): 12693-12701 doi: 10.1029/2019GL085409 [10] HAGGERTY C C, SHAY M A, DRAKE J F, et al. The competition of electron and ion heating during magnetic reconnection[J]. Geophysical Research Letters, 2015, 42(22): 9657-9665 doi: 10.1002/2015GL065961 [11] HOSHINO M. Energy partition between ion and electron of collisionless magnetic reconnection[J]. The Astrophysical Journal Letters, 2018, 868(2): L18 doi: 10.3847/2041-8213/aaef3a [12] BIRN J, HESSE M. Energy release and conversion by reconnection in the magnetotail[J]. Annales Geophysicae, 2005, 23(10): 3365-3373 doi: 10.5194/angeo-23-3365-2005 [13] EASTWOOD J P, PHAN T D, DRAKE J F, et al. Energy partition in magnetic reconnection in Earth’s magnetotail[J]. Physical Review Letters, 2013, 110(22): 225001 doi: 10.1103/PhysRevLett.110.225001 [14] PRIEST E, FORBES T. Magnetic Reconnection[M]. Cambridge: Cambridge University Press, 2000 [15] AUNAI N, BELMONT G, SMETS R. Energy budgets in collisionless magnetic reconnection: Ion heating and bulk acceleration[J]. Physics of Plasmas, 2011, 18(12): 122901 doi: 10.1063/1.3664320 [16] WANG S, CHEN L J, BESSHO N, et al. Energy conversion and partition in the asymmetric reconnection diffusion region[J]. Journal of Geophysical Research: Space Physics, 2018, 123(10): 8185-8205 doi: 10.1029/2018JA025519 [17] LU S, LU Q M, HUANG C, et al. The transfer between electron bulk kinetic energy and thermal energy in collisionless magnetic reconnection[J]. Physics of Plasmas, 2013, 20(6): 061203 doi: 10.1063/1.4811119 [18] LU S, PRITCHETT P L, ANGELOPOULOS V, et al. Magnetic reconnection in Earth’s magnetotail: Energy conversion and its earthward–tailward asymmetry[J]. Physics of Plasmas, 2018, 25(1): 012905 doi: 10.1063/1.5016435 [19] EASTWOOD J P, GOLDMAN M V, PHAN T D, et al. Energy flux densities near the electron dissipation region in asymmetric magnetopause reconnection[J]. Physical Review Letters, 2020, 125(26): 265102 doi: 10.1103/PhysRevLett.125.265102 [20] ZHOU M, ASHOUR-ABDALLA M, DENG X H, et al. Observation of three-dimensional magnetic reconnection in the terrestrial magnetotail[J]. Journal of Geophysical Research:Space Physics, 2017, 122(9): 9513-9520 doi: 10.1002/2017JA024597 [21] ZHOU M, DENG X H, ZHONG Z H, et al. Observations of an electron diffusion region in symmetric reconnection with weak guide field[J]. The Astrophysical Journal, 2019, 870(1): 34 doi: 10.3847/1538-4357/aaf16f [22] FUSELIER S A, VINES S K, BURCH J L, et al. Large-scale characteristics of reconnection diffusion regions and associated magnetopause crossings observed by MMS[J]. Journal of Geophysical Research: Space Physics, 2017, 122(5): 5466-5486 doi: 10.1002/2017JA024024 [23] WEBSTER J M, BURCH J L, REIFF P H, et al. Magnetospheric multiscale dayside reconnection electron diffusion region events[J]. Journal of Geophysical Research: Space Physics, 2018, 123(6): 4858-4878 doi: 10.1029/2018JA025245 [24] FU H S, VAIVADS A, KHOTYAINTSEV Y V, et al. How to find magnetic nulls and reconstruct field topology with MMS data?[J]. Journal of Geophysical Research: Space Physics, 2015, 120(5): 3758-3782 doi: 10.1002/2015JA021082 [25] FU H S, CAO J B, VAIVADS A, et al. Identifying magnetic reconnection events using the FOTE method[J]. Journal of Geophysical Research: Space Physics, 2016, 121(2): 1263-1272 doi: 10.1002/2015JA021701 [26] WANG Z, FU H S, VAIVADS A, et al. Monitoring the spatio-temporal evolution of a reconnection X-line in space[J]. The Astrophysical Journal Letters, 2020, 899(2): L34 doi: 10.3847/2041-8213/abad2c [27] WANG Z, FU H S, LIU C M, et al. Electron distribution functions around a reconnection X-line resolved by the FOTE method[J]. Geophysical Research Letters, 2019, 46(3): 1195-1204 doi: 10.1029/2018GL081708 [28] BURCH J L, TORBERT R B, PHAN T D, et al. Electron-scale measurements of magnetic reconnection in space[J]. Science, 2016, 352(6290): eaaf2939 doi: 10.1126/science.aaf2939 [29] PHAN T D, DRAKE J F, SHAY M A, et al. Ion bulk heating in magnetic reconnection exhausts at Earth’s magnetopause: Dependence on the inflow Alfvén speed and magnetic shear angle[J]. Geophysical Research Letters, 2014, 41(20): 7002-7010 doi: 10.1002/2014GL061547 [30] FU H S, CAO J B, CAO D, et al. Evidence of magnetic nulls in electron diffusion region[J]. Geophysical Research Letters, 2019, 46(1): 48-54 doi: 10.1029/2018GL080449 [31] CHEN Z Z, FU H S, WANG Z, et al. First observation of magnetic flux rope inside electron diffusion region[J]. Geophysical Research Letters, 2021, 48(7): e2020GL089722 doi: 10.1029/2020GL089722 [32] FU H S, VAIVADS A, KHOTYAINTSEV Y V, et al. Intermittent energy dissipation by turbulent reconnection[J]. Geophysical Research Letters, 2017, 44(1): 37-43 doi: 10.1002/2016GL071787 [33] WANG Z, FU H S, CHEN X H, et al. The effect of current on magnetic null topology during turbulent reconnection[J]. The Astrophysical Journal, 2022, 927(1): 119 doi: 10.3847/1538-4357/ac4eed [34] BIRN J, BOROVSKY J E, HESSE M, et al. Scaling of asymmetric reconnection in compressible plasmas[J]. Physics of Plasmas, 2010, 17(5): 052108 doi: 10.1063/1.3429676 -
-
下载:
图(7) / 表(1)
计量
- 文章访问数: 455
- HTML全文浏览量: 102
- PDF下载量: 125
-
被引次数:
0(来源:Crossref)
0(来源:其他)
