Kedkanok Sitarachu
Dr. Suwicha Wannawichian
2
Jupiter in our Solar system
3
Structure of Jupiter’s Magnetic Field
4
http://www.faulkes-telescope.com/
http://www.taringa.net/
Galilean moons
Io
Ganymede
Europa
Calisto
Io’s Geological Properties
Joshepshoer.com
8
Planetary Magnetic Field
and Magnetic Footprint
http://lasp.colorado.edu
Kivelson et al., 2004
10
vpar decrease
vperp increase
vpar increase
vperp decrease
12
Jupiter’s Magnetic field structure
B increase
vperp increase
vpar decrease
B decrease
vperp decrease
vpar increase
http://www.planetaryexploration.net
B
vpar
decrease
vperp increase
vperp decrease
vpar
increase
B0
15
UV imaging by HST/STIS
Main oval
Io’s magnetic footprint
Power of emission
Jupiter plasma equator
Io’s orbit
Schneider and Tauger 1995
magnetic footprint brightness
Apply the fitted equation for other data sets
z=0
distance between Io’s orbit and Jupiter plasma equator
19
Io’s magnetic footprint brightness and
its system III longitudes
Wannawichian, et al. [2010]
Observation by CASSINI spacecraft
The variation of plasma environment near
the satellite was revealed
22
First peak of Io’s magnetic footprint
emission on Dec 28, 2000
Interception location:116.02
highest plasma density:19.49
23
First peak of Io’s magnetic footprint
emission in 2001
24
Second peak of Io’s magnetic footprint
emission on February, 26-28, 2007
25
Summarized locations where plasma
density are expected to be highest
time
Interception
location
highest
plasma
density
locations
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
124.67
26
Discussion
 the regions where plasma density is
expected to highest were found to be in
different longitudes.
 longitudinal distances between
interception locations and Io’s longitudes
where plasma density is expected to be
highest were found to be different in each
data set.
 It implies that the shape of plasma torus
may change over time.
27
Conclusion
 Io’s system III longitudes, at which the
density at plasma equator is expected to
be highest, appear to vary at times.
 The plasma in the torus appears not to be
rigidly distributed.
 These results provide direct evidence of
the variation of the locations where
plasma density is expected to be highest
that was indicated by Io’s magnetic
footprint emissions.
28
Acknowledgement
 Dr. Suwicha Wannawichian
 Development and Promotion of Science
and Technology Talents Project
 National Astronomical Research Institute
of Thailand
 Members of Astronomical Laboratory,
Chiangmai University
 Department of Physics and Materials
Science, Chiangmai University
29
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 4
steradians
Clarke et al.,
31
2005
Clarke et al., 1998, 2004
Satellites in this study
Enceladus
Europa
Io
Enceladus’ 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
32
www.nasa.gov, www.ultimateuniverse.n
Open-loop Alfvèn model and the
electron beam
Gurnett and Goertz (1981), Crary and Bagenal (1997)
• Alfvèn waves travel from the interaction
region at Io to the torus boundary at high
latitude.
•The reflections of Alfvèn waves take place
causing some of the waves to be reflected and
some to continue into Jupiter’s ionosphere.
• 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)
33