Expansion and Shrinking of the Martian Topside Ionosphere
Expansion and Shrinking of the Martian Topside Ionosphere
复制标题
火星上部电离层的扩张和收缩
DOI：
10.1029/2019ja027077
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Halekas
中科院分区：
文献类型：
--
作者：
Dubinin;Fraenz;Pätzold;McFadden;Halekas
火星大气和挥发性演化探测器在火星上层（≥200公里）电离层的观测表明，该区域对外部（太阳极紫外线通量、太阳风和行星际磁场[IMF]）和内部（地壳磁场）驱动因素的变化非常敏感。随着太阳辐照度的增加，电离层变宽，而随着太阳风动压的增加，电离层变小。因此，太阳天顶角为60-70°的电离层上层边界可以从~ 400 km移动到~ 1200 km。在夜侧电离层也观察到类似的趋势。当AtPdyn≥1-2 nPa时，夜侧电离层变得非常破碎和耗竭。另一方面，随着太阳极紫外线通量的增加，夜侧电离层的离子密度显著增加（可达10倍）。上层电离层的大振幅运动也随着IMF横流分量值的变化而发生。高度超过300-400公里的上层电离层对IMF横流分量的方向也很敏感，或者相应地，对太阳风运动电场的方向也很敏感。电离层相对于theVsw×BIMFdirection变得非常不对称，这种不对称在夜侧强烈增强。与北半球非磁化低地上的电离层相比，南半球昼侧强磁场区域上方的电离层明显密度更大，并向更高的高度扩展。地壳磁场也保护了夜面电离层不被从日面运来的等离子体填满。悬垂的IMF深入电离层并积极影响电离层的结构。弱磁场和相应的弱磁场力对电离层的影响很小。随着感应磁场强度的增加，由磁场压力和磁场张力驱动的输运运动似乎加剧，白天侧局部离子密度明显降低。在夜侧观察到不同的趋势。北半球低地上空的夜侧电离层离子密度高于南半球，表明来自日侧的等离子体输运是夜侧电离层的主要来源。太阳风、IMF和太阳辐照度的不断变化，加上地壳磁场源的行星旋转，导致火星上层电离层的不断膨胀/收缩和重新配置。
The observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the topside (≥200 km) ionosphere of Mars show that this region is very responsive to the variations of the external (solar extreme ultraviolet flux, solar wind, and interplanetary magnetic field [IMF]) and internal (the crustal magnetic field) drivers. With the growth of the solar irradiance the ionosphere broadens while with increase of the solar wind dynamic pressure it shrinks. As a result, the upper ionospheric boundary at solar zenith angles of 60–70° can move from ∼400 to ∼1,200 km. Similar trends are observed at the nightside ionosphere. AtPdyn≥ 1–2 nPa the nightside ionosphere becomes very fragmented and depleted. On the other hand, the ion density in the nightside ionosphere significantly (up to a factor of 10) increases with the rise of the solar extreme ultraviolet flux. Large‐amplitude motions of the topside ionosphere also occur with variations of the value of the cross‐flow component of the IMF. The upper dayside ionosphere at altitudes of more than 300–400 km is sensitive also to the direction of the cross‐flow component of the IMF or, correspondingly, to the direction of the motional electric field in the solar wind. The ionosphere becomes very asymmetrical with respect to theVsw×BIMFdirection and the asymmetry strongly enhances at the nightside. The topside ionosphere above the areas with strong crustal magnetic field in the dayside southern hemisphere is significantly denser and expands to higher altitudes as compared to the ionosphere above the northern nonmagnetized lowlands. The crustal magnetic field also protects the nightside ionosphere from being filled by plasma transported from the dayside. The draping IMF penetrates deeply into the ionosphere and actively influences its structure. Weak fields and, correspondingly, weak magnetic field forces only slightly affect the ionosphere. With increase of the induced magnetic field strength the transport motions driven by the magnetic field pressure and field tensions seem to be intensified and we observe that the local ion densities at the dayside considerably decrease. A different trend is observed at the nightside. The ion density in the nightside ionosphere above the northern lowlands is higher than in the southern hemisphere indicating that plasma transport from the dayside is the main source of the nightside ionosphere. Nonstop variations in the solar wind, the IMF and the solar irradiance together with planetary rotation of the crustal magnetic field sources lead to a continuous expansion/shrinking and reconfiguration of the topside ionosphere of Mars.
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DOI：
10.1002/2017ja024126
发表时间：
2017-07
期刊：
Journal of Geophysical Research: Space Physics
影响因子：
--
作者：
E. Dubinin;M. Fraenz;M. Pätzold;J. Mcfadden;P. Mahaffy;F. Eparvier;J. Halekas;J. Connerney;David A. Brain;B. Jakosky;Oleg L Vaisberg;Lev Zelenyi
通讯作者：
E. Dubinin;M. Fraenz;M. Pätzold;J. Mcfadden;P. Mahaffy;F. Eparvier;J. Halekas;J. Connerney;David A. Brain;B. Jakosky;Oleg L Vaisberg;Lev Zelenyi
火星快车2号观测到的火星电离层太阳辐照度对电离层上部和逃逸通量的影响
影响因子：
2.4
作者：
Dubinin E;M. Fraenz;M. Pätzold;D. Andrews;O. Vaisberg;L. Zelenyi;S. Barabash
通讯作者：
S. Barabash
冷离子从火星电离层逸出
影响因子：
2.4
作者：
M. Fränz;E. Dubinin;D. Andrews;S. Barabash;H. Nilsson;A. Fedorov
通讯作者：
A. Fedorov
太阳辐照度对火星上层电离层和离子通量、火星快车和 MAVEN 观测的影响
DOI：
--
发表时间：
2016
期刊：
影响因子：
--
作者：
E. Dubinin;M. Fraenz;M. Paetzold;J. Mcfadden;F. Eparvier;D. Brain;B. Jakosky;D. Andrews;S. Barabash
通讯作者：
S. Barabash
MAVEN 观测到的火星电离层。
影响因子：
2.4
作者：
E. Dubinin;M. Fraenz;M. Pätzold;J. Mcfadden;J. Halekas;J. Connerney;B. Jakosky;Oleg L Vaisberg;Lev Zelenyi
通讯作者：
Lev Zelenyi