NOPR Collection:

Sodar Observations of March 1978 Tornado at Delhi

2016-11-09T05:58:50Z

Title: Sodar Observations of March 1978 Tornado at Delhi Authors: Singal, S P; Aggarwal, S K; Gera, B S Abstract: An unprecedented tornado struck North Delhi in the evening of 17 Mar. 1978. Effects due to this tornado appeared on the records of sodar operating at the National Physical Laboratory at a distance of about 10 km from the place of its occurrence. Primarily a thick elevated layer was noticed at a height around 300 m and undulations in the surface-based layer occurred after the event. The periodicity and frequency spectrum of these undulations were derived by autocorrelation and power spectral density techniques. Both strong randomness and periodicity appeared to exist. Page(s): 69-71

Counter-Electrojet Associated Changes in the Equatorial Anomaly: Part II-Jicamarea Radar Observations of Reversal of Upward Drift

2016-11-09T05:55:45Z

Title: Counter-Electrojet Associated Changes in the Equatorial Anomaly: Part II-Jicamarea Radar Observations of Reversal of Upward Drift Authors: Jain, A R Abstract: Published F-region vertical ion drift observations for Jicamarca are analyzed in conjunction with ground magnetic field data (H component) for Huancayo and Fuquene. A significant correlation is found between the changes in these drifts and electrojet intensity parameter. During significantly strong counter-electrojet events the drifts are. found to reverse from upward to the downward direction. This provides a direct evidence of electrical coupling between equatorial E- and F-regions. Page(s): 67-68

Radiation from Open-ended Coaxial Line in Warm Plasma Column Having Central Conductor along Its Axis

2016-11-09T05:53:18Z

Title: Radiation from Open-ended Coaxial Line in Warm Plasma Column Having Central Conductor along Its Axis Authors: Choudhary, R S; Sharma, D R Abstract: The radiation pattern of an open-ended coaxial line excited in the TEM mode in the warm plasma column having central conductor along its axis is studied. The field. Distribution at the open end cross-section of the coaxial line is assumed to be equivalent to the vector sum of magnetic current rings of various radii, ranging from the outer radius of the inner conductor to the inner radius of the outer conductor of the coaxial line at the open end. The radiation field is obtained as a vector sum of field components due to individual rings of magnetic current. It is found that the resulting radiation pattern of the open-ended coaxial line is greatly influenced by the warm plasma nature of the plasma medium and hydrodynamic admittance boundary conditions. Page(s): 65-67

Dispersion in Spaced Receiver Fading Observations at Thumba

2016-11-09T05:48:36Z

Title: Dispersion in Spaced Receiver Fading Observations at Thumba Authors: Patel, V P; Chandra, H Abstract: About 800 spaced fading records obtained at Thumba during the year 1967 have been examined for the skewness of the cross-correlation functions. For nearly 40-50% of cases the cross-correlation curves are symmetric. Positive skewness parameter is found in about 30-40% of cases while negative skewnessis seen in only 20-30% of cases. These results appear to be close to the results for TiruchirapaIIi obtained by using cross-spectral analysis. Page(s): 64-65