Dynamic processes in the ionosphere during magnetic storms from the Kharkov incoherent scatter radar observations
L. F. Chernogor
Kharkov V. Karazin National University, Kharkov, Ukraine
Ye. I. Grigorenko,
V. N. Lysenko,
and V. I. Taran
Institute of the Ionosphere, National Academy of Sciences of Ukraine, Ministry of Education and Science of Ukraine, Kharkov, Ukraine
Abstract
[1] Results of studying the ionosphere behavior during
several magnetic storms of various intensities are presented. The
features of pronounced negative ionospheric disturbances
accompanying the severe magnetic storms on 25 September 1998
and 29-30 May 2003 ( Kp 8) are considered. Among them there
are a decrease in the electron density by a factor of 3-4, uplifting of
the ionospheric
F2 layer by 100-160 km, increase in the
temperature of the charged and neutral atmospheric components,
and infringement of plasma transfer processes and thermal balance
in the ionosphere-plasmasphere system. In the morning of 25
September 1998, an unusual increase in the upward plasma drift
velocity was registered. On 29-30 May 2003 during the storm main
phase, a depletion of the relative density of hydrogen ions by more
than an order of magnitude was observed that could manifest an
emptying of the magnetic flux tube over Kharkov. These effects are
explained in terms of thermospheric disturbances, Joule heating,
particle precipitation, penetration of magnetospheric electric fields
to midlatitudes, the shift of the main ionospheric trough and related
structures toward the radar latitude, etc. The ionospheric storm on
20-21 March 2003 had two phases. Its strong negative phase
proceeded against a background of a minor geomagnetic
disturbance ( Kp 5). The destabilizing impact of the electric field
pulse and traveling atmospheric disturbance generated by
magnetospheric substorms could be the cause of the change in the
storm phase that occurred in the sunset period.
Received 4 July 2005; revised 25 September 2006; accepted 6 July 2007; published 26 October 2007.
Keywords: ionosphere; magnetic storms; incoherent scatter radar observations.
Index Terms: 2431 Ionosphere: Ionosphere/magnetosphere interactions; 2788 Magnetospheric Physics: Magnetic storms and substorms; 6969 Radio Science: Remote sensing.
![AGU](/journals/articleCitationLogo.gif)
Powered by TeXWeb (Win32, v.2.0).
|