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Low-Energy Proton Bombardment of Carbon Dioxide

2016-11-29T10:02:12Z

Title: Low-Energy Proton Bombardment of Carbon Dioxide Authors: Ray, K D; Bhutani, K.K.; Ghosh, S N Abstract: Carbon dioxide, the major constituent of Martian and Venusian atmospheres, was bombarded by protons having energy in the range 0.5 to 2 keV. The excited spectra in order of intensity consisted of Angstrom and 3PG system of CO₂ comet tail bands of CO⁺ and H_ɑ, and H_β lines. It was observed that the intensities of Angstrom and 3PG bands increase and those of comet tail bands of CO⁺ and H_β line decrease with proton energy. The excitation of the above bands has been attributed to the dissociation of CO₂ and charge exchange with protons. The spectra excited by proton bombardment were compared with those obtained by microwave discharge of CO₂ and their differences explained. Page(s): 416-418

Acceleration of Charged Particles in Magnetospheric Neutral Plasma Sheet

2016-11-29T09:59:07Z

Title: Acceleration of Charged Particles in Magnetospheric Neutral Plasma Sheet Authors: Khosa, P. N.; Rausaria, R. R.; Singh, R. N. Abstract: The reconnection of magnetic field lines in the neutral plasma sheet has been studied in the light of momentum conservation and charge neutrality. The effect of field variations and plasma conductivity on the charged particle dynamics has been studied. It is found that the charged particles emerging out of the neutral plasma sheet are energized. It is argued that the reconnection process would make the plasma sheet unstable. The onset of likely instabilities in the neutral plasma sheet and their geophysical implication has been briefly outlined. Page(s): 407-415

Effects of Magnetic & Solar Activity on HF Communication Via F2 Region

2016-11-29T09:57:43Z

Title: Effects of Magnetic & Solar Activity on HF Communication Via F2 Region Authors: Aggarwal, S.; Reddy, B. M. Abstract: High frequency propagation via F2 region continues to be the most important means of long distance communication. This is especially so in India. In order to evaluate how solar and magnetic disturbances affect the MUF parameters on a short-term basis, a comprehensive programme of study was undertaken. The early results of the programme indicate that for moderate magnetic activity at low latitudes the effect of increased f₀F2 is compensated for by increased hmF2 and the resultant MUF changes are not very significant. For relatively intense magnetic activity, the trends are more definite on an average basis, but the departures are not distinguishable from the extremes of the day-to-day random fluctuations. However, it is observed that some major solar Hares, though they are not followed by magnetic storms, do produce large depressions in the MUF values which can be included in the short-term predictions. Page(s): 401-406

Some Observations of Ionospheric-Transferred Modulation Effects

2016-11-29T09:54:36Z

Title: Some Observations of Ionospheric-Transferred Modulation Effects Authors: Rao, C. S. R.; Roy, J. M.; Chandra, Mahesh Abstract: In view of the increasing number of high power transmitters in the If-mf bands, the problem of cross-modulation has assumed considerable importance. Soon lifter a high power transmitter in mf band came into operation at Calcutta, it was reported that a few transmitters located in the Eastern Zone were getting transferred modulation from this transmitter. Some experiments were, therefore, undertaken by the Research Department of AIR to study this phenomenon in detail. In this paper the results of these observations regarding the variation of the transferred modulation with the modulating frequency and the carrier frequency of the disturbing transmitter are presented and compared with theoretical results. Page(s): 396-400