Solar and Interplanetary Disturbances causing Moderate Geomagnetic Storms

Journal of astrophysics and astronomy

Santosh Kumar1¹  M. P. Yadav¹  Amita Raizada¹ 

[1] Department of P.G. Studies and Research in Physics and Electronics, R. D. University, Jabalpur (M. P.) 482 001, India.$$

关键词: Solar flares;    active prominences and disappearing filaments;    sunspot numbers;    geomagnetic storms.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

The effect of solar and interplanetary disturbances on geomagnetospheric conditions leading to 121 moderate geomagnetic storms (MGS) have been investigated using the neutron monitor, solar geophysical and interplanetary data during the period 1978–99. Further, the duration of recovery phase has been observed to be greater than the duration of main phase in most of the cases of MGS. It has further been noted that Ap-index increases on sudden storm commencement (SSC) day than its previous day value and acquires maximum value on the day of maximum solar activity. Generally, the decrease in cosmic ray (CR) intensity and Dst begins few hours earlier than the occurrence of MGS at Earth. Furthermore, negative Bz pointing southward plays a key causal role in the occurrence of MGS and the magnitude and the duration of Bz and Bav also play a significant role in the development of MGS. The solar features H𝛼, X-ray solar flares and active prominences and disappearing filaments (APDFs) which have occurred within lower helio-latitudinal/helio-longitudinal zones produce larger number of MGS. Solar flares seem to be the major cause for producing MGS.

【 授权许可】

Unknown