1 Kedkanok Sitarachu Dr. Suwicha Wannawichian 2 Jupiter in our Solar system 3 Structure of Jupiterβs Magnetic Field 4 Galilean moons Io Ganymede Europa Calisto 5 Ioβs Geological Properties 6 Planetary Magnetic field and Magnetic footprint 7 ππ£ π£ πΉ =π πΈ+ ×π΅ =π ππ‘ π ππ£π₯ πBπ£π¦ = m ππ‘ ππ£π¦ ππ΅π£π₯ = m ππ‘ π2 π£π¦ (ππ΅)2 ππ£π₯ ππ΅ =m 2 = π£π¦ ππ‘ ππ‘ π π2 ( 2 ππ‘ β ππ΅ 2 )π£π¦ π =0 8 plasmaβs thermal energy : 5 eV 1 Kinetic energy : ππ£ 2 1 1 2 2 ππ£ = π(π£ππππ 2 2 2 vpar decrease 2 ) + π£πππ vperp increase vpar increase vperp decrease Adiabatic invariant : 2 ππ£ππππ π= 2π΅ 9 Jupiterβs Magnetic field structure B increase vperp increase vpar decrease B decrease vperp decrease vpar increase http://www.planetaryexploration.net 10 B decrease Adiabatic invariant : 2 ππ£ππππ π= 2π΅ vpar decrease vpar increase vperp increase vperp decrease B increase 11 B vpar decrease vperp increase vperp decrease πΌ0 vpar increase B0 Magnetic moment is conserved : ππ£ 2 π ππ2 πΌ0 2π΅0 = ππ£ 2 π ππ2 90° 2π΅ πΌ0 = π ππβ1 ( π΅0 π΅ ) If πΌ < πΌ0 , the particles can pass through Jupiterβs Ionosphere and result magnetic footprint. 12 UV imaging by HST/STIS Main oval Ioβs magnetic footprint 13 π = ππΌπ π½πΌπ Power of emission P = (2π πΌπ πΈ0 )(2π πΌπ πΈ0 )( π β π΅πΌπ π πβ π 2 ) π0 π΅πΌπ Jupiter plasma equator π Ioβs orbit 14 Schneider and Tauger 1995 z = -6.75sin(ππΌπΌπΌ - 108.3ο°) 15 Apply the fitted equation for other data sets magnetic footprint brightness z = -6.75sin(ππΌπΌπΌ - bο°)___(1) z=0 distance between Ioβs orbit and Jupiter plasma equator 16 Ioβs magnetic footprint brightness and its system III longitudes Wannawichian, et al. [2010] 17 Observation by CASSINI spacecraft The variation of plasma environment near the satellite was revealed π ππΌπΌπΌ = (ππ + π1 sin ππΌπΌπΌ β π0 )π ππ : π§2 β 2 π» ________(2) z: Jupiterβs magnetospheric electron density at Io(~ 2000 cm-3 ) [Kivelson et al., 2004] variation amplitude of plasma density suggested to be 20% ofππ [Steffl et al, 2004]. Ioβs system III longitude where the amplitude of plasma variation is expected to be highest Ioβs distance from Jupiter plasma equator H: scale height, and π1 : π0 : π»= 2ππ 3π2 = 0.5 RJ, based on the best fitted value for ten-year observation data [Wannawichian, 2012 (submitted)] 18 πβ π brightness ππΌπΌπΌ = (1 + 0.2 sin ππΌπΌπΌ β π0 )π π§2 β 2 0.5 ________(3) 19 First peak of Ioβs magnetic footprint emission on Dec 28, 2000 Interception location:116.02 highest plasma density:19.49 20 First peak of Ioβs magnetic footprint emission in 2001 21 Second peak of Ioβs magnetic footprint emission on February, 26-28, 2000 22 Summarized locations where plasma density are expected to be highest time Interception location Highest plasma density Distance from interception location 1999 102.44 286.75 184.31 14-16/12/2000 113.08 46.45 66.60 28/12/2000 116.02 19.49 96.53 2001 109.07 46.59 62.48 23-25/12/2007 138.11 5.43 107.68 26-28/12/2007 231.74 59.51 172.23 7-11/3/2007 272.19 147.51 124.68 23 Discussion ο the regions where plasma density is expected to highest were found to be in different longitudes. ο longitudinal distances between interception locations and Ioβs longitudes where plasma density is expected to be highest were found to be different in each data set. ο It implies that the shape of plasma torus may change over time. 24 Conclusion ο Ioβs system III longitudes, at which the density at plasma equator is expected to be highest, appear to vary at times. ο The plasma in the torus appears not to be rigidly distributed. ο These results provide direct evidence of the variation of the locations where plasma density is expected to be highest that was indicated by Ioβs magnetic footprint emissions. 25 Acknowledgement ο Dr. Suwicha Wannawichian ο Development and Promotion of Science and Technology Talents Project ο National Astronomical Research Institute of Thailand ο Members of Astronomical Laboratory, Chiangmai University ο Department of Physics and Materials Science, Chiangmai University 26 Thank you Interior of Jupiter Planetary Aurora www.nasa.gov, NASA/Goddard Space Flight Center 1999 Planets Earth Jupiter Saturn Bsurface (G) 0.1 4 0.2 Rotation period (hr) 24 9.92 10.7 Distance to magnetopause (Rplanet) 11 RE 45 RJ 21 RS Auroral brightness (kR) 1-100 10-10,000 1-100 1 kRayleigh (kR) = 109 photon/sec from a 1 cm2 column of the atmosphere radiated into 4ο° steradians Clarke et al., 28 2005 Clarke et al., 1998, 2004 Satellites in this study Enceladus Europa Io Enceladusβ water plumes near its southern pole taken by the ISS/NAC camera onboard Cassini spacecraft Ganymede Satellites Io Europa Ganymede Enceladus Diameter (km) 3,630 3,140 5,260 498 Geology Volcanically active, non magnetized Icy surface, non magnetized Icy surface, magnetized Geologically active, icy surface, non magnetized 29 www.nasa.gov, www.ultimateuniverse.n Open-loop Alfvèn model and the electron beam Gurnett and Goertz (1981), Crary and Bagenal (1997) β’ Alfvèn waves travel from the interaction region at Io to the torus boundary at high latitude. β’The reflections of Alfvèn waves take place causing some of the waves to be reflected and some to continue into Jupiterβs ionosphere. β’ Also the electron beam created at high latitude could be reflected to the opposite hemisphere and create a spot leading the main Alfvèn wing spot. Blue: Alfvèn current system Red: electron beams Bonfond et al., (2008) 30
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