Physics
Scientific paper
May 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995jgr...100.7971h&link_type=abstract
Journal of Geophysical Research (ISSN 0148-0227), vol. 100, no. A5, p. 7971-7985
Physics
6
Geomagnetic Pulsations, Geomagnetism, Plasma Waves, Plasmas (Physics), Troughs, Explorer 50 Satellite, Gyrofrequency, Helium Ions, Ion Cyclotron Radiation, Magnetopause, Solar Wind Velocity, Spectrum Analysis, Viking Orbiter Spacecraft, Wave Propagation
Scientific paper
An analysis of concurrent Pc 1 pulsation activity (0.2-0.6 Hz) recorded on the ground at Mawson, Antarctica (70 deg S magnetic latitude (MLAT); 19 deg E magnetic longitude (MLONG); L = 8), and on board the Viking polar-orbiting satellite, when the spacecraft was located near apogee (13.5 x 10(exp 3) km) from 50-77 deg MLAT above the northern ionosphere, shows that simultaneous pulsations were observed only when Viking's conjugate point was within 60-70 deg MLAT and 30 deg E-33 deg W MLONG, an extent of about 1000 km in latitude and 1700 km in longitude. Spectral analysis confirms that the waves responsible for these pulsations are electromagnetic ion cyclotron (EMIC) waves that have propagated to the spacecraft and ground from the geomagnetic equator. For the intervals when the waves were on field lines above and equatorward of Mawson, convective EMIC wave modeling shows wave growth is dominant below the equatorial He(+) gyrofrequency. Waves generated on field lines poleward of Mawson exhibit frequencies above the equatorial He(+) gyrofrequency. These propagate to Mawson, most likely through a purely proton plasma rather than a multi-ion environment. Frequency shifts in the Pc 1 activity at Mawson appear to be directly linked to solar wind velocity and flux variations measured by IMP 8. For certain intervals these linked observations are consistent with an interpretation based on the velocity and flux changes altering the radical position of the magnetopause through pressure balance considerations. This, in turn, changes the magnitude of the ambient magnetic field in the equatorial plasma trough and consequently the ion gyrofrequency and EMIC growth rate. Pc 3-5 activity was recorded at Mawson in conjunction with the Pc 1 frequency shifts and in association with rapid B(sub IMF) variations. The changes in the temperature anisotropy and energy of the resonant ions in the plasma trough, which are causing the Pc 1 emission changes, are associated with the entry of dayside Pc 3-5 pulsation energy into the dayside magnetosphere.
Erlandson Robert E.
Fraser Brian J.
Hansen H. J.
Menk Frederick W.
No associations
LandOfFree
Ground satellite observations of Pc 1 magnetic pulsations in the plasma trough 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 Ground satellite observations of Pc 1 magnetic pulsations in the plasma trough, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ground satellite observations of Pc 1 magnetic pulsations in the plasma trough will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1061315