[P-PS08] 惑星科学

[PPS08-04] A Juno / Hisaki joint effort to monitor Jupiter’s electron-belt radiation during Juno’s cruise

*Daniel Santos-Costa¹、Chihiro Tao²、Hajime Kita³、Tomoki Kimura⁴、Jack Connerney⁵、Steven Levin⁶、Scott Bolton¹、Go Murakami⁷、Sooman Han⁸、Fuminori Tsuchiya³、Hiroaki Misawa³、Atsushi Yamazaki⁷ (1.Southwest Research Institute、2.NICT、3.Tohoku University、4.RIKEN、5.NASA Goddard Space Flight Center、6.JPL/CalTech、7.ISAS/JAXA、8.University of Tokyo)

キーワード：Jupiter, Juno, Hisaki, Radiation-belt

At frequencies between 50 MHz and several GHz, Jupiter’s radio spectrum is dominated by synchrotron radiation, emitted by high energy electrons magnetically confined in a region close to the planet (e.g. Jovian radiation belt). For over the past 40 years ground-based observations have demonstrated that this radio signal simultaneously varies over different time scales, from less than a day up to year periods. These variations are controlled by the spatial evolution of the relativistic electron population surrounding the planet inside Io’s orbit. Recent analyses of Hisaki EUV data of Io plasma torus’ east-west asymmetry tend to support that large-scale dawn-dusk electric fields, driven by solar irradiation and solar wind on different time scales, can govern the dynamical behavior of Jupiter’s electron belt. We combine different datasets of Juno (magnetometer), solar radio flux and irradiation, Hisaki (extreme ultraviolet, after Nov. 2013), and ground-based observations of Jupiter (GAVRT before 2013; VLA, GMRT after 2012) with established models of solar wind propagation and solar radiation at Jupiter to investigate the synchrotron emission variability during Juno’s cruise (mid-Aug. 2011 to June 2016). In this paper, we discuss our preliminary results for periods when Juno is in near alignment with the Sun and Jupiter, and witnesses - while en route to Jupiter - large perturbations in the interplanetary magnetic field which would suggest that some features in the solar wind could be responsible for the occurrence of variations in the synchrotron emission a couple of weeks later.