Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations

Details Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations

Oct 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998jgr...10323611s&link_type=abstract

Journal of Geophysical Research, Volume 103, Issue A10, p. 23611-23622

Physics

Plasma Physics

5

Magnetospheric Physics: Magnetosphere/Ionosphere Interactions, Magnetospheric Physics: Mhd Waves And Instabilities, Magnetospheric Physics: Plasma Waves And Instabilities, Space Plasma Physics: Waves And Instabilities

Scientific paper

This paper describes amplitude modulations in the frequency range 0-500 mHz of ELF/VLF (0.5-4.0 kHz) radio wave power recorded throughout 1993 and 1995 at Halley and South Pole stations, Antarctica, which lie in approximately the same magnetic meridian and at geomagnetic latitudes (Λ) of 61° and 74°, respectively. Data from the intermediate automatic geophysical observatories P2 and P3 (Λ=70° and 72°, respectively) were also analyzed where available. In agreement with earlier work, spectrograms have revealed the frequent daytime (typically 0700-1700 MLT) occurrence of modulations lying almost entirely within the two period ranges: 10-60 s and 4-6 s. The first range corresponds to quasiperiodic (QP) emissions, while the latter is typical of the two-hop whistler mode echo period in the plasmatrough, and the events are termed periodic emissions (PEs). QP occurrence rates higher than some earlier studies (335 station-days out of 667 examined) may be attributable to the sensitive spectral analysis technique. The type I QPs (i.e., those correlated with geomagnetic pulsations observed at South Pole and/or P2/P3) were consistent with an upstream wave driver, controlled by the IMF cone angle. Type II QPs (uncorrelated with magnetic pulsations) were always accompanied by PEs, suggesting a link between the two, reinforced by a frequently observed steady increase in period in both phenomena, especially during the morning, possibly associated with increasing densities due to upward flow of photoionized plasma from the ionosphere after dawn. Here we propose that type II QPs are driven by field line resonant ULF waves which in turn are generated by field-aligned currents arising from PE induced electron precipitation.

Affiliated with

Also associated with

No associations

Rating

Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Periodic and quasiperiodic ELF/VLF emissions observed by an array of Antarctic stations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1097951