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IPS Observations of Short-Time Scale Interplanetary Activity

Published online by Cambridge University Press:  12 April 2016

Pradeep Gothoskar  and
A. Pramesh Rao
Pradeep Gothoskar
Affiliation:
National Centre for Radio Astrophysics, TIFR, Poona University Campus, Pune 411 007.India
A. Pramesh Rao
Affiliation:
National Centre for Radio Astrophysics, TIFR, Poona University Campus, Pune 411 007.India

Abstract

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We have carried out a program of continuous Interplanetary Scintillation (IPS) monitoring of the interplanetary activity using Ooty Radio Telescope (ORT). From May 1990 to March 1991, during the 22nd solar maximum, a few radio sources were monitored to provide long stretches of IPS data with a high-time resolution of few minutes. These observations covered 0.3 to 0.8 AU region (12° to 70° elongations) around the sun at several heliographic latitudes. During the observation, we detected 33 short-time scale IPS events which had significant variation in the scintillation index and solar wind velocity. These were considered to be due to travelling interplanetary disturbances.

A multi-component model of plasma density enhancement was developed to estimate the geometry and physical properties of these IPS events. Detailed analysis of 20 of these events suggests, 1. fast IPS events were interplanetary signatures of Coronal Mass Ejections (CMEs), 2. the average mass and energy of these events was ~ 1016 gm and 1033 erg respectively, 3. 80% of IPS events were associated with X-ray flares on the sun and 50% were associated with geomagnetic activity at earth. Detailed study of the multi-component model suggests IPS observations at smaller elongations (hence at higher radio frequencies) are more suited to detect fast-moving interplanetary disturbances such as produced by CMEs.

Keywords

Solar WindSolar Terrestrial PhysicsInterplanetray Scintillations
Type
IPS and Other Remote Sensing Measurements
Information
International Astronomical Union Colloquium , Volume 154: Solar and Interplanetary Transients , 1996 , pp. 225 - 228
Copyright
Copyright © Kluwer 1997

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