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http://dx.doi.org/10.5140/JASS.2006.23.3.217

OSCILLATIONS OF THE OUTER BOUNDARY OF THE OUTER RADIATION BELT DURING SAWTOOTH OSCILLATIONS  

Kim Jae-Hun (Department of Astronomy and Space Science, Chungbuk National University)
Kim Kyung-Chan (Department of Astronomy and Space Science, Chungbuk National University)
Lee Dae-Young (Department of Astronomy and Space Science, Chungbuk National University)
Kim Hee-Jeong (Institute for Basic Science Research, Chungbuk National University)
Publication Information
Journal of Astronomy and Space Sciences / v.23, no.3, 2006 , pp. 217-226 More about this Journal
Abstract
We report three sawtooth oscillation events observed at geosynchronous orbit where we find quasi-periodic (every 2-3 hours) sudden flux increases followed by slow flux decreases at the energy levels of ${\sim}50-400keV$. For these three sawtooth events, we have examined variations of the outer boundary of the outer radiation belt. In order to determine L values of the outer boundary, we have used data of relativistic electron flux observed by the SAMPEX satellite. We find that the outer boundary of the outer radiation belt oscillates periodically being consistent with sawtooth oscillation phases. Specifically, the outer boundary of the outer radiation belt expands (namely, the boundary L value increases) following the sawtooth particle flux enhancement of each tooth, and then contracts (namely, the boundary L value decreases) while the sawtooth flux decreases gradually until the next flux enhancement. On the other hand, it is repeatedly seen that the asymmetry of the magnetic field intensity between dayside and nightside decreases (increases) due to the dipolarization (the stretching) on the nightside as the sawtooth flux increases (decreases). This implies that the periodic magnetic field variations during the sawtooth oscillations are likely responsible for the expansion-contraction oscillations of the outer boundary of the outer radiation belt.
Keywords
sawtooth oscillation; outer boundary; outer radiation belt; L value;
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1 Baker, D. N., Mason, G. M., Figueroa, O., Colon, G., Watzin, J. G., & Aleman, R. M. 1993, IEEE Trans. Geosci. Remote Sensing, 31, 531   DOI   ScienceOn
2 Belian, R D., Cayton, T. E., & Reeves, G. D. 1995, in Space Plasmas, vol.89, eds. M. Ashour-Abdalla, T. Chang, & P. Dusenberry (Washington DC: AGU), p.143
3 Henderson, M. G., Reeves, G. D., Skoug, R, Thomsen, M. F., Denton, M. H., Mende, S. B., Immel, T. J., Brandt, P. C., & Singer, H. J. 2006, JGR, 111, A01S90   DOI
4 Kim, K. C., Lee, D. Y., Lee, E. S., Choi, C. R., Kim, K. H., Moon, Y. J., Cho, K. S., Park, Y. D., & Han, W. Y. 2005, JGR, 110, A09223   DOI
5 Lee, D. Y. & Lyons, L. R. 2004, JGR, 109, A04202   DOI
6 Lee, D. Y., Lyons, L. R., & Yumoto, K. 2004, JGR, 109, A04201   DOI
7 Nakamura, R., Isowa, M., Kamide, Y., Baker, D. N., Blake, J. B., & Looper, M. 2000, JGR, 105, 15875   DOI
8 Henderson, M. G. 2004, Geophys. Res. Lett., 31, L11804   DOI   ScienceOn