Indian Journal of Radio & Space Physics

(Bimonthly)  

 

 ISSN : 0367-8393    

 CODEN : IJRSAK

VOLUME 32

NUMBER 1

FEBRUARY 2003

 

CONTENTS

RPA aeronomy experiment onboard the Indian satellite SROSS-C2¾Some important aspects of the payload and satellite

  5

S C Garg, J R Anand, M Bahl, P Subrahmanyam, S S Rajput, H K Maini, P Chopra, T John, S K Singhal, Vishram Singh, Dhan Singh, U N Das, S M Bedekar, P Soma, Venkteshwarlu & D P Goel

 

 

 

Influence of geomagnetic activity on the occurrence of midlatitude ionogram-  recorded spread-F 

 

G G Bowman & I K Mortimer

16

 

 

A new look at the ionospheric current system

21

R G Rastogi

 

 

 

Abrupt change in total ozone column over Indian Antarctic station

38

O P Tripathi & S L Jain

 

 

 

Solar plasma activated decametric radio emission of non-Io origin from Jupiter  magnetosphere

 

S K Bose & A B Bhattacharya

 

 

 

Notes

 

 

 

Short-term influence of coronal mass ejections on geomagnetic disturbances

52

Pankaj K Shrivastava, G N Singh & Devendra Shrivastava

 

 

 

 

Indian Journal of Radio & Space Physics 

Vol. 32, February 2003, pp. 5-15

   

RPA aeronomy experiment onboard the Indian satellite SROSS-C2 — Some important aspects of the payload and satellite

 

S C Garg, J R Anand, M Bahl, P Subrahmanyam, S S Rajput,

H K Maini, P Chopra, T John, S K Singhal, Vishram Singh & Dhan Singh

National Physical Laboratory, New Delhi 110 012

and

U N Das & S M Bedekar

ISRO Satellite Centre, Bangalore 560 017

and

P Soma, Venkteshwarlu & D P Goel

ISRO Satellite Telemetry & Tracking Centre, Bangalore 560 058

 

Received 5 November 2002; accepted 15 December 2002

An aeronomy payload of retarding potential analyser (RPA) consisting of an electron RPA, ion RPA and a potential probe (PP), designed and developed at the National Physical Laboratory, New Delhi, was flown onboard the Indian satellite SROSS-C2 on 4 May 1994, for making in situ measurements of F-region ionospheric plasma. The objective of the mission was to investigate the characteristics and energetics of the equatorial and low latitude ionosphere / thermosphere over the Indian region. The SROSS-C2 was a spin-stabilized orbiting satellite placed in an elliptical orbit having orbit inclination of 46.3°. The payload made simultaneous sampling of electron and ion plasma in the altitude range of 420-620 km for more than half a solar cycle from minima to maxima of the 23rd solar cycle activity. During initial phase of the mission, measurements were made in a higher orbit for a limited period of two months, while the satellite apogee was at 930 km keeping the perigee same. The total ion density, electron and ion temperatures, ion composition, supra-thermal electron flux and irregularities in electron and ion densities along the satellite orbit can be derived from the measurements. In this paper, some important aspects of the scientific payloads, the satellite and its orbital configuration, which are important in understanding the payload operation in space for data collection including the analysis of data and their interpretations, are described.

 

 

Indian Journal of Radio & Space Physics 

Vol. 32, February 2003, pp. 16-20

 

Influence of geomagnetic activity on the occurrence of midlatitudeionogram-recorded spread-F

 

G G Bowman & I K Mortimer

Department of Physics, The University of Queensland, Qld 4072, Australia

 

Received 27 September 2001; revised 9 October 2002; accepted 6 November 2002

Delayed spread-F occurrence as recorded by ionograms, following geomagnetic activity (GA) has been investigated using data from 88 stations located around the world. The spread-F occurrence is delayed progressively from one to three days, from subauroral to midlatitude regions. The equatorial latitudes show suppressed activity. An examination of daily spread-F occurrence values relative to the AE index reveals not only a main delay of one day, but also delays of two and three days. These delays involve prinicipally GA occurring around 0600 hrs LT.

 

 

 

Indian Journal of Radio & Space Physics 

Vol. 32, February 2003, pp. 21-37

 

 

A new look at the ionospheric current system

 

R G Rastogi

Department of Physics, Gujarat University, Ahmedabad 380 009

 

Received 30 October 2001; revised 30 September 2002; accepted 10 November 2002

The paper describes some regional anomalies in the solar daily variations of the northward X and eastward Y geomagnetic field by examining the data from individual stations during the International Geophysical Year (IGY) 1957-58. Around 30-40°N dip latitude the daily range of X showed a minimum and the range of Y a maximum, which is the characteristic of the Sq focus. No definite indications of such phenomenon were seen in the southern hemisphere. The low latitude maximum of DX around noon changed to midday minimum at high latitudes, not through a flat daily variation at focus latitudes. A forenoon minimum and an afternoon maximum of DX occurred at northern focus latitudes. A reverse feature occurred at southern focus latitude. It is suggested that the mid-latitude Sq current system is greatly affected by another low latitude current system as well as by the polar Sq current system. The daily variation of DY was reversed in the two hemispheres (the latitude of reversal at around 15°S in J-solstices and around 10°N during D-solstices) which suggests the invasion of summer current system over the winter current system. The global variation of DX and DY seem to be independent of each other. The direction of equatorial current vector departs significantly from the direction of the normal to the magnetic meridian or from the geographical east. The latitudinal extent of inter-focus currents in Europe-Asian sector contracts in June solstices and expands in December solstices, but in American sector it shifts southward in December and northward in June solstices. These anomalous features of global current system seem to be associated with abnormal distribution of the earth’s magnetic field in the northern and southern hemispheres.

 

 

 

 Indian Journal of Radio & Space Physic

Vol. 32, February 2003, pp.21-37

 

Abrupt change in total ozone column over Indian Antarctic station

O P Tripathi & S L Jain

Radio and Atmospheric Sciences Division, National Physical Laboratory, New Delhi 110 012

 

Received 22 October 2001; revised received 15 February 2002; accepted 26 September 2002

The solar radiation at five wavelengths, namely, 300 nm, 305 nm, 312 nm, 940 nm and 1020 nm has been measured using narrow band (2.5 nm FWHM) filters with a microprocessor-based sun-photometer from January 1997 to February 1998 on hourly basis on all clear days at Maitri, an Indian Antarctic station (70°45¢S, 11°45¢E), during sixteenth Indian Scientific Antarctic expedition. The total column ozone has been estimated from these measurements. Very low ozone values have been observed during Antarctic spring, which confirmed the continuity of ozone hole phenomenon. Abrupt increase in total ozone column has been observed during ozone hole period. This observation has been confirmed by the same event in total ozone mapping spectrometer (TOMS) measurements and may be attributed to planetary wave phenomenon.

 

Indian Journal of Radio & Space Physics 

Vol 32, February 2003, pp. 43-51

 

 

Solar plasma activated decametric radio emission of
non-Io origin from Jupiter magnetosphere

S K Bose* & A B Bhattacharya

Department of Physics, Kalyani University, Kalyani 741 235

Received 22 January 2002; revised received 20 June 2002; accepted 4 October 2002

The interaction between solar plasma with Jovian magnetosphere has been highlighted by studying the correlation between decametric radio emission from the Jupiter with different solar plasma parameters and also with the interplanetary magnetic field feature and the heliospheric current sheet extent. Significance of the correlation is tested with usual statistical technique. Also the Chree-superposed-epoch analysis has been performed with lag-days correction for the observed solar plasma parameters at 1AU, considering high values of occurrence probability of decametric radio-emission of non-Io origin from Jupiter as epoch days. The results of Chree analysis support the correlation study.

 

 

Indian Journal of Radio & Space Physics

Vol. 32, February 2003, pp. 52-54

 

Notes

 

Short-term influence of coronal mass ejections on geomagnetic disturbances

Pankaj K Shrivastava1, G N Singh2 &

Devendra Shrivastava1

1Department of Physics, Govt. New Science College, Rewa (M.P.) 486 001

2Deptartment of Physics, Sudarshan Degree College, Lalgaon, Distt. Rewa (M.P.) 486 115

Received 6 December 2001; revised 27 May 2002; accepted 25 November 2002

Coronal mass ejections (CMEs) are described as a turbulent interplanetary phenomena at 1AU, which influence the interplanetary medium as well as disturbances in geomagnetic field. The CMEs represent large scale changes in the solar corona. In this note the relation of CMEs with geomagnetic activity has been studied for the period of 1988-1993. It is found that CMEs in association with B-type solar flares are most effective in producing disturbances in geomagnetic field.