2. Description of the Experiment

[6]  The experiment was carried out on 18-22 August 2003 from 1600 to 2000 LT (  LT = UT +4 hours). The following radio paths were used: Khabarovsk (the geographic coordinates are j = 47.5^oN, l = 134.5^oE) to Rostov on Don ( j = 47.3^oN, l = 39.7^oE), Irkutsk ( j =51.8^oN, l = 104^oE) to Rostov on Don and Inskip (England, j = 53.8^oN, l = 2.8^oW) to Rostov on Don. To perturb the ionosphere by powerful HF radioemission, heating facility SURA ( j = 56.1^oN, l = 46.1^oE) was used. The facility operated in the following regime: 5 min of emission and 5 min of pause starting from the beginning of each hour. The ordinary polarization wave was emitted at the frequency of the pumping wave f_p close to the critical frequency of the ionosphere f_oF2 (f_p f_oF2).

Figure 1

[7]  The effective emission power PG was 40 or 80 MW depending on the working frequency f_p. To control the radio wave condition at the Khabarovsk-SURA, Irkutsk-SURA, and Inskip-SURA paths, the reception of LFM signals at the paths Khabarovsk-Nizhny Novgorod ( j = 56.1^oN, l = 44.1^oE), Irkutsk-Nizhny Novgorod, and Inskip-Nizhny Novgorod was organized. The LFM sounders in Irkutsk and Khabarovsk operated the first and the second halves of each hour, respectively. The emission of the LFM signals started at 0, 5, 10,... 55 min of each hour with the following parameters: starting frequency 4 MHz, end frequency 30 MHz, and rate of the frequency returning 100 kHz s ^-1. On 20 August 2003 when the LFM sounders in Irkutsk and Khabarovsk did not operate, the emission of the LFM sounder from England (Inskip) was received. This sounder operated in the 5-min regime starting from the second minute of each hour with the following parameters: starting frequency 4.2 MHz, end frequency 30 MHz, and rate of the frequency returning 100 kHz s ^-1. The LFM signals in the Rostov-on-Don reception point were received by the oblique V antenna oriented to the SURA heating facility. The same antenna was used to receive the etalon signals of the RVM station at a frequency of 9996 kHz. The RVM transmitter operated in a regime of continuous emission of the carrier from 0 to 8 s and from 30 to 38 s of every hour. During the operation of the SURA facility the RVM transmitter was used as a Doppler HF radar at the RVM sounding path Moscow ( j =55.3 ^o N, l = 38.7^oE) to SURA-Rostov on Don for diagnostics of artificial small-scale magnetically oriented irregularities. In the Nizhny Novgorod reception point the LFM signals were received using the vertical collapsible whip. The geometry of the experiment is shown in Figure 1.