New phenomenon observed on board the ISS during a RF ionosphere modification.

A quantitative analysis is presented of the data on modification of the ionosphere by high-power radio emission from the SURA heating experiment run on October 2, 2007 (18:40 – 19:00 UT). The Sura facility was working in the mode of periodic heating at the radio frequency (RF) of 4.30 MHz. The modulation frequency was close to the frequency of natural Alfven oscillations of plasma in the local magnetic flux tube. The effects of modification were observed onboard the Russian Segment of the International Space Station (RS ISS). The observations have provided more than 1500 images of a bright local glow, which appeared within the field of view of the TV camera as the ISS was passing close to the location of the Sura facility. The brightness of aurora reached some hundreds of kiloRayleighs. The compact bright aurora appeared North-East of the heating facility and was moving East in the image plane. The analysis of helio-geophysical conditions did not reveal any significant anomalies during the experiment. A low power of the heating RF emission and high intensity of the observed aurora suggest that the local glow wasn't due directly to HF heating of ionosphere, but rather might be caused by the particle precipitation artificially stimulated by the heating effects, such as modification of the ionosphere over the SURA heating facility, which forms the base of the magnetic flux tube (and the standing wave node) whose natural Alfven oscillations have a period close to the modulation period of the heating HF emission. The Alfven mode of the magnetic tube could be intensified during the experiment by a short (less than 1 min) and weak (amplitude of about 2 nT) pulse in the planetary geomagnetic field that occurred at 18:47:30 UT.