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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Effects of solar wind density and velocity variations on the Martian ionosphere and plasma transport - a MHD model study
AU - Song, Yihui
AU - Lyu, Haoyu
AU - Cao, Jinbin
AU - Wu, Xiaoshu
AU - Liu, Yang
AU - Li, Shibang
AU - Wang, Siqi
AU - Wild, Jim
AU - Zhou, Chenling
AU - Wang, Jianxuan
AU - Chen, Nihan
PY - 2023/12/20
Y1 - 2023/12/20
N2 - Solar wind dynamic pressure, consisting solar wind density 𝑛𝑠𝑤 and velocity 𝑉𝑠𝑤, is an important external driver that controls Martian plasma environment. In this study, a 3D magnetohydrodynamic model is applied to investigate the separate influences of solar wind density and velocity on the Martian ionosphere. The spatial distributions of ions in the dayside and near nightside ionosphere under different 𝑛𝑠𝑤 and 𝑉𝑠𝑤 are analyzed, as well as the ion transport process. We find that for the same dynamic pressure condition, the ionosphere extends to higher altitudes under higher solar wind density, indicating that a solar wind velocity enhancement event is more efficient at compressing the Martian ionosphere. A higher 𝑉𝑠𝑤 will result in a stronger induced magnetic field, shielding the Martian ionosphere, preventing the penetration of solar wind particles. For the same dynamic pressure, increasing 𝑛𝑠𝑤 (decreasing 𝑉𝑠𝑤) leads to a higher horizontal ion velocity, facilitating day-to-night plasma transport. As a result, the ionosphere extends farther into the nightside. Also, the ion outflow flux is larger for high 𝑛𝑠𝑤, which may lead to a higher escape rate. Moreover, the strong crustal fields in the southern hemisphere also cause significant effect to the ionosphere, hindering horizontal ion transport. An additional outflow channel is also provided by the crustal field on the southern dayside, causing different responses of flow pattern between local and global scale while the solar wind condition is varied.
AB - Solar wind dynamic pressure, consisting solar wind density 𝑛𝑠𝑤 and velocity 𝑉𝑠𝑤, is an important external driver that controls Martian plasma environment. In this study, a 3D magnetohydrodynamic model is applied to investigate the separate influences of solar wind density and velocity on the Martian ionosphere. The spatial distributions of ions in the dayside and near nightside ionosphere under different 𝑛𝑠𝑤 and 𝑉𝑠𝑤 are analyzed, as well as the ion transport process. We find that for the same dynamic pressure condition, the ionosphere extends to higher altitudes under higher solar wind density, indicating that a solar wind velocity enhancement event is more efficient at compressing the Martian ionosphere. A higher 𝑉𝑠𝑤 will result in a stronger induced magnetic field, shielding the Martian ionosphere, preventing the penetration of solar wind particles. For the same dynamic pressure, increasing 𝑛𝑠𝑤 (decreasing 𝑉𝑠𝑤) leads to a higher horizontal ion velocity, facilitating day-to-night plasma transport. As a result, the ionosphere extends farther into the nightside. Also, the ion outflow flux is larger for high 𝑛𝑠𝑤, which may lead to a higher escape rate. Moreover, the strong crustal fields in the southern hemisphere also cause significant effect to the ionosphere, hindering horizontal ion transport. An additional outflow channel is also provided by the crustal field on the southern dayside, causing different responses of flow pattern between local and global scale while the solar wind condition is varied.
KW - mars
KW - plasma
KW - space weather
KW - MHD modelling
KW - space physics
U2 - 10.1029/2023JA031788
DO - 10.1029/2023JA031788
M3 - Journal article
VL - 128
JO - Space Weather
JF - Space Weather
SN - 1542-7390
IS - 12
M1 - e2023JA031788
ER -