Forbush decreases in cosmic ray intensity and large scale magnetic configuration of interplanetary shocks

Badruddin, (2000) Forbush decreases in cosmic ray intensity and large scale magnetic configuration of interplanetary shocks. Il nuovo cimento C, 23 C (3). pp. 217-226. ISSN 1826-9885

ncc7481.pdf - Published Version

Download (156kB) | Preview
Official URL:


We present the results of an analysis to study the effects of shock front, sheath region and driver gas (ejecta) on the transient decreases of cosmic-ray intensity. In this work interplanetary plasma and field data along with hourly neutron monitor cosmic-ray intensity records have been subjected to superposed epoch analysis. We have also studied the variations in interplanetary plasma/field parameters (viz. solar wind speed, magnetic field strength and its variance) and cosmic-ray intensity during the passage of individual transient interplanetary structures. The sudden decrease in intensity starts after the arrival of certain shocks. The shock front itself is not sufficient for the Forbush decreases but the turbulence generated in sheath region appears to be its main cause. A shock structure is considered which explains the results. The essential feature of this structure is that the extent of the shock front is much more than the ejecta and magnetic turbulence is usually present in the limited region of sheath. Based on this, we explain the reason behind the observation that all the shock-associated disturbances do not produce Forbush decreases on reaching the Earth.

Item Type: Article
Uncontrolled Keywords: Interplanetary space ; Cosmic rays
Subjects: 500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.5 Meteorologia (Classificare qui l'atmosfera) (Classificare la previsione e le previsioni di specifici fenomeni meteorologici in 551.64; classificare la Micrometeorologia in 551.66) > 551.52 Termodinamica, interazioni atmosferiche con la superficie terrestre, temperature, radiazioni > 551.527 Radiazioni (per fenomeni ottici, vedi 551.565) > 551.5276 Radiazioni cosmiche (Include il rumore cosmico) (Classificare qui i raggi cosmici)
Depositing User: Marina Spanti
Date Deposited: 09 Mar 2020 14:50
Last Modified: 09 Mar 2020 14:50

Actions (login required)

View Item View Item