1 / 25

Global Distribution of E quatorial P lasma B ubbles in the Pre-midnight Sector

Global Distribution of E quatorial P lasma B ubbles in the Pre-midnight Sector. 3 Mar. 2005 Jaeheung PARK. What is EPB?. E quatorial P lasma B ubble : sharp decrease of plasma density in equatorial region. General Features of EPB. micro-structure  wave scattering.

fred
Download Presentation

Global Distribution of E quatorial P lasma B ubbles in the Pre-midnight Sector

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Global Distribution of Equatorial Plasma Bubbles in the Pre-midnight Sector 3 Mar. 2005 Jaeheung PARK

  2. What is EPB? • Equatorial Plasma Bubble : sharp decrease of plasma density in equatorial region

  3. General Features of EPB micro-structure  wave scattering • Scale lengths : several meters ~ several hundred kilometers • Local time : sunset to sunrise • Field-aligned structure • Forming a vertical channel • Adverse effects on the radio communication

  4. Rayleigh-Taylor instability • When heavy fluid sits above lighter fluid in a gravitational field • Bubbles of light fluid rise into the heavier medium

  5. Generalized Rayleigh-Taylor instability Recombination loss • F-region Pedersen conductivity • F-region plasma density ; Kil et al. [2004] • vertical drift speed • F-region dynamo ; Fejer et al. [1999]

  6. Observational Instruments • date of launch : Dec. 21, 1999 (near the solar maximum) • sun-synchronous orbit : fixed at 2250 LT • altitude : 685 km • plasma density and electron temperature (1) KOMPSAT-I ( KOREA )

  7. (2) DMSP F15 (U.S.) • sun-synchronous orbit : fixed at 2130 LT • altitude : 840 km • electron density, electron temperature, ion fraction, and drift speed

  8. DMSP F15 KOMPSAT-1

  9. Seasonal-Longitudinal distribution of EPBs

  10. Sunset-node theory of Tsunoda (1985) ③ ④ ⑤ ① ②

  11. Generalized Rayleigh-Taylor instability • F-region Pedersen conductivity • F-region plasma density ; Kil et al. [2004] • vertical drift speed • F-region dynamo ; Fejer et al. [1999] Global verification using in-situ measurements

  12. Fig. GUVI disk-scan image in February and August, 2002.

  13. evening prereversal enhancement (EPE) • vertical drift speed • F-region dynamo ; Fejer et al. [1999]

  14. Magnetic declination angle? American Atlantic American Atlantic

  15. TIMED/GUVI disk-scan images at nighttime show large longitudinal and seasonal variations in the OI 135.6-nm radiance. The intensity of the anomaly does not precisely conform to the intensity of the background. The GUVI observations indicate that the F-region morphology near the F peak can be different from the morphology on the topside that has been extensively studied using DMSP data. The background plasma density is higher in the south But the northern anomaly is stronger than the southern anomaly Fig. Composite GUVI 135.6-nm scan image at 2150 LT on Jan. 29, 2002.

  16. Conclusions • The S/L distribution of EPBs was common to both KOMPSAT-1 and DMSP F15, whose orbits have different local times and altitudes. • The importance of ambient plasma density and vertical drift speed was verified globally. • Their relative influenceswere proved to be dependent on the season. • March equinox : drift-dominated • June solstice : density-dominated • December solstice : possible dominated by bottomside phenomena

  17. Plasma blobs? KOMPSAT-1 DMSP-F15

  18. S/L distribution

More Related