Sura 2One year after the first Sura campaign a second one was conducted, between the 18th of September to the first of October 1991. Participating were Bo Thidé, Thomas Leyser, Mattias Waldenvik and Eugen Veszelei from the Swedish Institute of Space Physics, Uppsala Division and Lev Erukhimov, Vladmir Frolov, Saveliy Grach and Gregori Komrakov from the local Radiophysical Research Institute of Nizhniy Novgorod.This time the primary goal was to investigate specific SEE features such as the "Broad Upshifted Maximum" and the "Downshifted Maximum" and the conditions for its appearance and splitting, and the "wide continuum" in the lower sideband. For the "Downshifted Maximum" (DM) a continuous relation to the heating frequency was found for a large variation of heating frequencies. Cut-off effects of the BUM and the SEE in general were studied through comparison between SEE during the heater pulse and SEE after the heater pulse. Studies of the growth and relaxation of general SEE provided a more continuous picture of the SEE development, which was investigated on John Silver. Frequencies used for heating was the fourth, fifth, sixth and seventh harmonic of the electron cyclotron frequency and frequency stepping around those frequencies. The so called Yampolsky experiment, where sampling of SEE where taken between heating pulses, failed to give any conclusive results. The team also searched for Doppler shifts within the heater pulse, which was to be possible to detect with a varying modulation of the pump wave. Once more double frequency experiments were conducted and the intensity of the "Arithmetic Mean Peak" and its dependence on the difference between the two heating frequencies were measured. It seemed to show a dependence on the heating frequency, near harmonics or not. In the radar probing experiments the temporal development of the plasma lines were investigated. It was found that they generally appeared with a temporal delay of of 1.1 to 1.5 ms with respect to the heater. a lack of scattering near resonance was detected. Possible Doppler effects in radar at cyclotron harmonics was examined in both phase and amplitude and also with the aid of SEE. A lack of scattering near resonance was discovered. In some probe experiments the ERP was held constant while the frequency offset for the probe pulse in respect to the heater was varied. In others the frequency offset was held constant while the heater ERP and the probe pulse were varied. A pilot experiment using the HF pump wave as a diagnostic tool probing the magnetosphere was carried out, but the results were inconclusive. John Silver with an fast ADC unit were set up for phase and amplitude measurements. From the HP3585A hardcopies of spectra can be found. An index of the data files, stored in the hard drive under the names of fadc#, by Mattias Waldenvik, is available for internal use, under the name "Sura 2 - Fast Timescale Data". Thus stored are experiments on resonance search at electron cyclotron harmonics, relaxation measurement (phase/amplitude), power stepping, cubic interaction and arithmetic mean experiments as well as probe pulse experiments, where the heater was added to with short pulses of a frequency with a few tens of kilohertz offset.  Thomas Leyser and Bo Thidé by the instumental equipment.
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