Details

Autor(en) / Beteiligte

• Han, S.
• Murakami, G.
• Kita, H.
• Tsuchiya, F.
• Tao, C.
• Misawa, H.
• Yamazaki, A.
• Nakamura, M.

Titel

Investigating Solar Wind‐Driven Electric Field Influence on Long‐Term Dynamics of Jovian Synchrotron Radiation

Ist Teil von

• Journal of geophysical research. Space physics, 2018-11, Vol.123 (11), p.9508-9516

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• 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 of DLL(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 while DLL(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. Key Points Radial diffusion coefficient derived from dawn‐to‐dusk electric field fluctuations controlled by solar wind conditions is introduced The coefficient is comparable to dynamo electric field influence on Jupiter's upper atmosphere at the outer part of the radiation belt Our radial diffusion model provides the best reproduction of Jovian synchrotron radiation observed in the past