A new shock fitting procedure for the MHD Rankine-Hugoniot relations for the case of small He(2+)ippage
文献类型：期刊论文
| 作者 | Lin, C. C.; Chao, J. K.; Lee, L. C.; Lyu, L. H.; Wu, D. J. |
| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
 |
| 出版日期 | 2006-09-16 |
| 卷号 | 111期号:A9页码:A09104 |
| 关键词 | BOW SHOCK DISCONTINUITY OBSERVATIONS INTERPLANETARY SHOCKS MAGNETIZED PLASMA HEAT-CONDUCTION SLOW SHOCKS SOLAR WIND NORMALS ANISOTROPY MINIMUM |
| ISSN号 | 0148-0227 |
| 英文摘要 | To study MHD shocks in space, it is important to find the shock frame of reference from the observed plasma and magnetic field parameters. These shock parameters have to satisfy the Rankine-Hugoniot relations. In this study we present a novel procedure for shock fitting of the one-fluid anisotropic Rankine-Hugoniot relations and of the time difference between two spacecraft observations in the case of small He2+ slippage. Here, a Monte-Carlo calculation and a minimization technique are used. The observed variables including the upstream and downstream magnetic fields, plasma densities, plasma betas, plasma anisotropies, W (the difference between the downstream and upstream velocities, W = V-2 - V-1), and Delta t (the time difference between two spacecraft observations) are used in our procedure where V is defined as the center of mass velocity of plasmas. A loss function based on a difference between the calculated and the observed values is defined, and the best fit solution is found by searching for the minimum loss function value. For shocks that cannot be fitted well, we introduce two new parameters in the modified RH relations, one in the normal momentum flux and the other in the energy flux equations. These two parameters are interpreted as the equivalent "normal momentum" and "heat" fluxes needed in the RH relations. They provide two degrees of freedom in the system, and their amounts can be estimated from our procedure. Several synthetic shocks are given to verify our procedure. We also apply this procedure to two interplanetary shocks observed by both the WIND and Geotail spacecraft. The results demonstrate that our method works for both the synthetic and the real shocks. We have shown that our method can provide accurate shock normal estimations for perpendicular and parallel shocks as well. Given that our model is based on the RH relations that do not include the effect of alpha particle (He2+) slippage, it can only be applied to the cases with an ignorable slippage pressure tensor. We have investigated the pressure tensor due to alpha particle slippage using the WIND spacecraft data. It is found that in general the slippage pressure is small in comparison with the thermal pressure of the system and can be ignored. Thus our model can be applied to most interplanetary shocks observed near the ecliptic plane. However, when the slippage pressure is large, the magnetic coplanarity theorem is not valid any more. A more general model that involves slippage pressure tensor is a major and important development that is beyond the scope of the present study. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 学科主题 | Astronomy & Astrophysics |
| 类目[WOS] | Astronomy & Astrophysics |
| 研究领域[WOS] | Astronomy & Astrophysics |
| 关键词[WOS] | BOW SHOCK ; DISCONTINUITY OBSERVATIONS ; INTERPLANETARY SHOCKS ; MAGNETIZED PLASMA ; HEAT-CONDUCTION ; SLOW SHOCKS ; SOLAR WIND ; NORMALS ; ANISOTROPY ; MINIMUM |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000240647900003 |
| 公开日期 | 2012-02-07 |
| 源URL | [http://159.226.72.40/handle/332002/3552]  |
| 专题 | 紫金山天文台_太阳和太阳系等离子体研究团组 |
| 作者单位 | 1.Natl Cent Univ, Inst Space Sci, Chungli 32001, Taiwan 2.Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China |
| 推荐引用方式 GB/T 7714 | Lin, C. C.,Chao, J. K.,Lee, L. C.,et al. A new shock fitting procedure for the MHD Rankine-Hugoniot relations for the case of small He(2+)ippage[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,2006,111(A9):A09104. |
| APA | Lin, C. C.,Chao, J. K.,Lee, L. C.,Lyu, L. H.,&Wu, D. J..(2006).A new shock fitting procedure for the MHD Rankine-Hugoniot relations for the case of small He(2+)ippage.JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,111(A9),A09104. |
| MLA | Lin, C. C.,et al."A new shock fitting procedure for the MHD Rankine-Hugoniot relations for the case of small He(2+)ippage".JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 111.A9(2006):A09104. |
入库方式： OAI收割
来源：紫金山天文台
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