Investigating Solar Wind‐Driven Electric Field Influence on Long‐Term Dynamics of Jovian Synchrotron Radiation
Investigating Solar Wind‐Driven Electric Field Influence on Long‐Term Dynamics of Jovian Synchrotron Radiation
复制标题
研究太阳风驱动电场对木星同步加速器辐射长期动力学的影响
DOI：
10.1029/2018ja025849
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Nakamura M.
中科院分区：
文献类型：
--
作者：
Han S.;Murakami G.;Kita H.;Tsuchiya F.;Tao C.;Misawa H.;Yamazaki A.;Nakamura M.
自20世纪50年代末首次在木星辐射带发现木星同步辐射以来，同步辐射时间变化的成因一直是木星辐射带研究的主要课题之一。据报道，JSR与太阳风冲压压力密切相关，可能存在时滞，这仍然是一个未解决的问题。在我们的研究中，黎明到黄昏电场调制太阳风冲压压力JSR变化的影响进行了研究。除了原始的扩散系数（DLL（UV）），一个新的扩散系数（DLL（Elec））取决于太阳风条件被应用到一个一维有损耗的径向扩散模型，我们重现了1971年和2018年初之间JSR的长期变化。在DLL（UV）= 3.0 × 10 - 10 L3 [s-1]的特定选择下，模拟的JSR与2005年以前的地面观测数据的相关系数为0.6，2005年以后的间歇观测数据也支持我们的模拟结果。我们认为，DLL（UV）是决定电子布居和JSR稳定分布的主要扩散模式，DLL（Elec）是控制JSR长期变化的次要模式。
Since the first discovery of Jovian Synchrotron Radiation (JSR) from Jovian radiation belt in late 1950s, origin of its time variations has been one of the main subjects of the Jovian radiation belt study. JSR is reported to be strongly correlated with solar wind ram pressure with a possible time lag, which remains an unsolved issue. In our study, the influence of dawn‐to‐dusk electric field modulated with solar wind ram pressure on JSR variations is investigated. Alongside the original diffusion coefficient (DLL(UV)), a new diffusion coefficient (DLL(Elec)) which is dependent on solar wind conditions is applied to a one‐dimensional lossy radial diffusion model, and we reproduce long‐term variations of JSR between 1971 and early 2018. For the specific choice ofDLL(UV) = 3.0 × 10−10L3[s−1], the correlation coefficient is found to be 0.6 between the simulated JSR and the ground observation data prior to 2005, and the intermittent observation after 2005 supports our simulation as well. We suggest that whileDLL(UV) is the primary mode of diffusion that determines the steady profile of electron population and JSR,DLL(Elec) serves as a secondary mode, which controls long‐term variations of JSR.