http://nopr.niscpr.res.in/handle/123456789/36644 2026-10-12T19:31:02Z http://nopr.niscpr.res.in/handle/123456789/36763 Title: Fine Structure Cooling Rates for Oxygen Authors: Jain, Renu; Baluja, K L; Setty, C S G K Abstract: Fine structure cooling rates of interest in the E-region, of the ground state of atomic oxygen, are calculated at various temperatures by using the most recent cross-sections based on <i>R</i>-matrix approximation. Six states are included in the total wave function of the e^- +O system. Four of these states are represented by Hartree-Fock approximation, while the two states of <i>¹S^e</i> symmetry are represented by more accurate configuration interaction wave functions. The results indicate that the cooling rates obtained by the present calculations are 25% lower than those currently in use. Page(s): 177-178 1983-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/36762 Title: Effect of Ion Collisions on Interaction of Longitudinal Electromagnetic Waves with Half-space Plasma Authors: Singh, R K; Phalswal, D R Abstract: The expressions for fields and penetration depth are derived and discussed for half-space (<i>z</i> > 0), filled with homogeneous, collisional and warm plasma. It is observed that the penetration depth <i>δ/δ_e</i>, (in the unit of electron penetration depth) remains constant in the vicinity of unity at low ion density (<i>ω_pi</i>/<i>ω_pe</i> =0.005), whereas for lower ion thermal velocity, the penetration depth increases and the wave gets highly reflected at higher ion thermal velocity. The penetration depth decreases for higher ion collision frequency and ion density. Page(s): 175-176 1983-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/36761 Title: Comments on Sunrise Effect in Atmospheric Electricity Authors: Mukku, V N R; Varshneya, N C; Khera, M K Abstract: By recalling the fact that ionosphere can be considered as an equipotential surface, it is concluded that sunrise effect in atmospheric electricity cannot be explained in terms of changes in ionospheric potential. Page(s): 174 1983-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/36760 Title: Microwave Propagation Characteristics over Arid Region Authors: Sarkar, S K; Dutta, H N; Reddy, B M; Rao, D Narayan Abstract: Microwave propagation characteristics at 1.9 GHz observed over arid region of India are presented. Troposcatter field strength has been found to vary from - 90 dBm to - 50 dBm. The nighttime hourly median field strength is higher as compared to the daytime median field strength but fade frequency is more during day than night. Association of signal levels with various meteorological parameters indicates that the signal level is not correlated well with surface refractivity, N₃; but it shows good agreement with spectral slope of refractive index fluctuation (<i>n</i>). Measured values of signals have been compared with the predicted values obtained from different theoretical models. Low order signal levels have been found to be comparable with the signal levels obtained from the model given for scattering, while high order signals agree with the values deduced from reflection theory. Page(s): 169-173 1983-10-01T00:00:00Z