V.V. Afonin

Plasma density variations observed on a satellite possibly related to seismicity

Abstract We discovered a reliable correlation between global distribution of seismic activity and ion density variations in the ionosphere on the basis of the analysis of a rather large data base of plasma density, which was recorded on board a Russian satellite Intercosmos 24 (more than 3000 orbits over the world). The best parameters to find a significant correlation between the two, are normalized standard deviation (NSD) and relative normalized standard deviation (RNSD). Maximal values of density NSD correlated with seismic activity are 10–20%. However, a clear correlation is found only for daytime (10–16 LT), quiet magnetic conditions and altitude range 500–700 km, while it disappears in nighttime and during magnetic storms. A mechanism of seismo-ionosphere coupling might be connected with slow gravity waves.

Satellite and ground-based measurements of the SAR-Arc phenomena

Abstract Data of the Intercosmos 24 (IC 24) satellite and the ground based complex optical and ionospheric measurements in the region of the stable auroral red (SAR)-arc are presented. Photometric observations were carried out at the Maimaga station (invariant latitude Λ =56.5°, geomagnetic longitude λ m =200°) and vertical incidence ionospheric soundings were made at Yakutsk (Λ =55.°, λ m =200°) and Zhigansk (Λ=60.4°, λ m =195°) stations. It is shown that when SAR-arc arises for the interval ∼ 15 min, the local minimum of the F-region electron density is formed, and in the ionograms typical signatures of the polarization jet or SAID are observed. Simultaneously, the height of the regular F2 layer increases. This evidences that strong electric field (E ∼ 100 mV/m) exists at the F2 layer heights. In this case, in addition to the SAR-arc energy sources, the effect of the ion-frictional heating is turned out to be important. Simultaneous measurements aboard the IC-24 satellite at the altitudes ∼500 km above the SAR-arc also show 3/5 times decreased electron density.. The electron temperature elevates up to ∼ 4500 K. At altitudes of 2400 km the ion density increases by 30 – 40% and T e rises up to 6300 K.

Development of Beam-Plasma Instability during the Injection a Low-Energy Electron Beam into the Ionospheric Plasma

Results are presented from an active experiment on the injection of charged particle beams into the ionospheric plasma. The experiment was carried out in 1992 onboard the Intercosmos-25 satellite and the Magion-3 daughter satellite (APEX). A specific feature of this experiment was that both the ion and electron beams were injected upward, in the same direction along the magnetic field. The most interesting results are the excitation of HF and VLF-LF waves and the generation of fast charged particle flows, which were recorded on both satellites.

Waves generated in the vicinity of the xenon plasma gun in the APEX-experiment

Abstract Wave and plasma observations were made in a close vicinity of a xenon gun, carried at altitudes near 500 km in the APEX-experiment. Wideband noise associated with neutral gas releases and steady beam currents were detected. In modulation regime even and odd harmonics of the beam modulation frequency were observed. A delay in wave emissions after modulated beam injection was terminated was also detected. This effect was accompanied by electron temperature and density disturbances as measured by a plasma density and temperature device.

Magnetic Field Excitation during Electron Beam Injection from the Intercosmos-25 Satellite (APEX)

Results of active experiments on electron beam injection from the Intercosmos-25 satellite into the ionospheric plasma are presented. A quasistatic magnetic field and the VLF-wave magnetic component are excited when an unmodulated electron beam with a current of Ibe⋍0.1 A and energy of ɛbe=mv2/2⋍10 keV is injected into the ambient plasma. The magnetic field excitation is attributed to the onset of plasma gradient instabilities.

Waves generated in the vicinity of Xenon plasma gun in the APEX-experiment

Abstract Wave and plasma observations were made in some neighborhood of a xenon gun, carried at altitudes near 500 km in the APEX-experiment. Wideband noise associated with neutral gas releases and steady beam currents were detested. In modulation regime even and odd harmonics of the beam modulation frequency were observed. Some delay in wave emissions after termination of modulated beam injection was detected as well. This effect was accompanied by the electron temperature and density disturbances as measured by a plasma density and temperature device.

Active experiments in space for the investigation of beam-plasma interactions. Results of the APEX project

Beam-plasma instabilities in the ionosphere caused by charged particle beams and Xe-neutral gas release are investigated. Special attention is paid to the injection into background plasma of an unmodulated electron beam with a current Ibe ≅ 0.1 A and energy ebe = mv22 ≅ 10 keV. Complex analysis of this problem is carried out with special data processing and with an approach similar to a laboratory-style experiment. The processes of ionospheric plasma heating, longitudinal plasma wave excitation and the analysis of thermal plasma ion disturbances during 1-s pulsed direct current (dc) injections are considered.