Kedkanok Sitarachu

Dr. Suwicha Wannawichian

Jupiter in our Solar system2

Structure of Jupiter’s Magnetic Field

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http://www.taringa.net/http://www.faulkes-telescope.com/

4

Io

Europa

Ganymede

Calisto

Galilean moons

Io’s Geological Properties

Joshepshoer.com

8Planetary Magnetic Field and Magnetic Footprint

Kivelson et al., 2004http://lasp.colorado.edu

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vperp decrease

vpar increase

vpar decrease

vperp increase

http://www.planetaryexploration.net

vperp increase

vpar decrease

B increase

vperp decrease

vpar increase

B decrease

Jupiter’s Magnetic field structure

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B

B 0

vperp increase

vpar decrease

vperp decrease

vpar increase

UV imaging by HST/STIS

Main oval

Io’s magnetic footprint

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Io’s orbit

Jupiter plasma equator

Power of emission

Schneider and Tauger 1995

mag

net

ic f

ootp

rint

brightn

ess

distance between Io’s orbit and Jupiter plasma equator

z=0

Apply the fitted equation for other data sets

Io’s magnetic footprint brightness and its system III longitudes

Wannawichian, et al. [2010]

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Observation by CASSINI spacecraft

The variation of plasma environment near the satellite was revealed

First peak of Io’s magnetic footprint emission on Dec 28, 2000

Interception location:116.02 highest plasma density:19.49

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First peak of Io’s magnetic footprint emission in 2001

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Second peak of Io’s magnetic footprint emission on February, 26-28, 2007

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Summarized locations where plasma density are expected to be highest

time Interceptionlocation

highestplasma 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

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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.

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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.

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AcknowledgementDr. Suwicha WannawichianDevelopment and Promotion of Science

and Technology Talents ProjectNational Astronomical Research Institute

of ThailandMembers of Astronomical Laboratory,

Chiangmai UniversityDepartment of Physics and Materials

Science, Chiangmai University

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Thank you

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Interior of Jupiter

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Planetary Aurora

Clarke et al., 1998, 2004

Clarke et al., 2005

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 4steradians

www.nasa.gov,

NASA/Goddard Space Flight Center 1999

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Satellites in this study

www.nasa.gov, www.ultimateuniverse.n

Io Europa Ganymede

Enceladus

Satellites Io Europa Ganymede Enceladus

Diameter (km) 3,630 3,140 5,260 498

GeologyVolcanically active, non magnetized

Icy surface, non magnetized

Icy surface, magnetized

Geologically active, icy surface, non magnetized

Enceladus’ water plumes near its southern pole taken

by the ISS/NAC camera onboard Cassini spacecraft

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Open-loop Alfvèn model and the electron beam

Bonfond et al., (2008)

• 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.

Blue: Alfvèn current systemRed: electron beams

• 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.

Gurnett and Goertz (1981), Crary and Bagenal (1997)