Penetration of polar electric fields to the nightside dip equator at times of geomagnetic sudden commencements

Abstract. We analyze the effects of the 2-day wave activity in the EEJ using one coherent scatter radar and eight magnetometer stations located close to the dip equator. The wavelet analysis of the magnetometer data reveals a 2-day signature in the semidiurnal geomagnetic tide. The E-region zonal background ionospheric electric field, derived from coherent radar measurements, shows 2-day oscillations in agreement with such oscillations in the magnetometers data. An anticorrelation between the amplitude of the tidal periodicites (diurnal and semidiurnal) and that of the 2-day signature is also shown in the electric fields. The results are compared with simultaneous observations of 2-day planetary wave in meridional winds and ionosonde data. Further, our results are discussed based on the analysis of the magnetic activity.

Download Full-text

Evidence of transmission of polar electric fields to the low latitude at times of geomagnetic sudden commencements

Journal of Geophysical Research Atmospheres ◽

10.1029/ja091ia03p03101 ◽

1986 ◽

Vol 91 (A3) ◽

pp. 3101 ◽

Cited By ~ 50

Author(s):

Takashi Kikuchi

Keyword(s):

Electric Fields ◽

Low Latitude ◽

Sudden Commencements

Download Full-text

Penetration electric fields at the nightside dip equator associated with the main impulse of the storm sudden commencement of 8 July 1991

Journal of Geophysical Research Atmospheres ◽

10.1029/2002ja009453 ◽

2002 ◽

Vol 107 (A12) ◽

pp. SIA 9-1-SIA 9-8 ◽

Cited By ~ 22

Author(s):

J. Hanumath Sastri

Keyword(s):

Electric Fields ◽

Sudden Commencement ◽

Storm Sudden Commencement ◽

Dip Equator

Download Full-text

Letter to the editor: Electric field fluctuations (25-35 min) in the midnight dip equatorial ionosphere

Annales Geophysicae ◽

10.1007/s00585-000-0252-2 ◽

2000 ◽

Vol 18 (2) ◽

pp. 252-256 ◽

Cited By ~ 4

Author(s):

J. Hanumath Sastri ◽

H. Luhr ◽

H. Tachihara ◽

T. -I. Kitamura ◽

J. V. S. V. Rao

Keyword(s):

Electric Field ◽

Electric Fields ◽

Geomagnetic Latitude ◽

Equatorial Ionosphere ◽

Plasma Drift ◽

F Region ◽

Vertical Drift ◽

Field Fluctuations ◽

Dip Equator ◽

Electric Fields And Currents

Abstract. Measurements with a HF Doppler sounder at Kodaikanal (10.2°N, 77.5°E, geomagnetic latitude 0.8°N) showed conspicuous quasi-periodic fluctuations (period 25-35 min) in F region vertical plasma drift, Vz in the interval 0047-0210 IST on the night of 23/24 December, 1991 (Ap = 14, Kp < 4-). The fluctuations in F region vertical drift are found to be coherent with variations in Bz (north-south) component of interplanetary magnetic field (IMF), in geomagnetic H/X components at high-mid latitude locations both in the sunlit and dark hemispheres and near the dayside dip equator, suggestive of DP2 origin. But the polarity of the electric field fluctuations at the midnight dip equator (eastward) is the same as the dayside equator inferred from magnetic variations, contrary to what is expected of equatorial DP2. The origin of the coherent occurrence of equatorial electric field fluctuations in the DP2 range of the same sign in the day and night hemispheres is unclear and merits further investigations.Key words: Ionosphere (electric fields and currents; equatorial ionosphere; ionosphere-magnetosphere interactions)

Download Full-text