| Project/Area Number |
06640573
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | Kochi National College of Technology |
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Principal Investigator |
IMAI Kazumasa Kochi National College of Technology, Department of Electrical Engineering, Associate Professor, 電気工学科, 助教授 (20132657)
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| Co-Investigator(Kenkyū-buntansha) |
TOMIZAWA Ichiro University of electro-communications, Sugadaira Space Radio Observatory, Associa, 菅平宇宙電波観測所, 助教授 (50111696)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Jupiter / Radio Emissions / Decametric wave / VLBI / Polarization |
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| Research Abstract |
The investigation of Jupiter's decameter-wavelength radio source locations and emission beam structure is very important for the study of the emission mechanism (Carr and Desch, 1976 ; Carr et al., 1983). Jupiter's rediation occurring during the so-called Io-B and Io-A storms is right-hand (RH) circularly or elliptically polarized. The Io-C storms, however, are often left-hand (LH) circularly polarized when observed in the vicinity of 18 MHz. Often a storm of long duration will begin in the Io-A region of central meridian longitude (CML) and end in the Io-C region, in which case it is not uncommon for the polarization sense to fluctuate back and forth between RH and LH in the transition region. It is generally believed that the Io-B and Io-A radiations are emitted in the extraordinary (X) mode, from within successive Io-energized flux tubes at the altitudes above the cloud-tops at which the wave frequency is only slightly higher than the electron gyrofrequency.
Since it is known that the field lines of Jupiter's nearly-dipolar magnetic field are directed from the northern to the southern Jovigraphic polar regions, it follows that the RH polarized Io-B and Io-A emissions come from near the northern rather than the southern foot of the Io-energized flux tube. The question is where do the LH polarized Io-C emissions come from? With our dual-polarization interferometer we expect to be able to measure the angular separation of the sources of the LH polarized and RH polarized bursts that occur within a few time seconds of each other with sufficient accuracy to determine whether they were located in the same or in opposite polar hemispheres.
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