P. K. Purohit
National Institute of Technical Teachers’ Training and Research
Dr. Pramod Kumar Purohit is Professor in Department of Applied Science, National Institute of Technical Teachers’ Training and Research Bhopal (Under Ministry of Human Resource Development, Govt. of India). He did his M.Sc. (Physics) and Ph.D. in communication Electronics (Physics) from Barkatullah University Bhopal. He has published/presented more than eighty papers/ articles in various Journals/Magazines/Conferences/Newspapers. He has been associated with several National and International research projects in related areas of research activity. He has supervised Eight Ph.D. and guiding 06 Students for Ph.D. degree in Physics and Electronics subject under the faculty of Science. He has participated in 22nd Indian Antarctic Scientific Expedition. He had done commendable work in Antarctic. For last 10 years his students are participating in Indian Antarctic Scientific program. He has written five books on Antarctica and participated/ presented papers in National /International seminar/ conferences. His area of research is ionospheric Physics.
The geomagnetic storm represents the most outstanding example of solar wind- magnetospheric interaction, which causes global disturbances in the geomagnetic field as well as the trigger ionospheric disturbances. We study the behaviour of ionospheric Total Electron Content (TEC) during the geomagnetic storms. For the present investigation we have selected 47 intense geomagnetic storms (Dst ≤ -100nT) that were observed during the solar cycle 23 i.e. during 1998- 2006. We then categorized these storms into four categories depending upon their solar sources like Magnetic Cloud (MC), Co-rotating Interaction Region (CIR), SH+ICME and SH+MC. We then studied the behaviour of ionospheric TEC at a mid latitude station Usuda (36.13N, 138.36E), Japan during these storm events produced by four different solar sources. During our study we found that the smooth variations in TEC are replaced by rapid fluctuations and the value of TEC is strongly enhanced during the time of these storms belonging to all the four categories. However, the greatest enhancements in TEC are produced during those geomagnetic storms which are either caused by Sheath driven Magnetic cloud (SH+MC) or Sheath driven ICME (SH+ICME). We also derived the correlation between the TEC enhancements produced during storms of each category with the minimum Dst. We found the strongest correlation exists for the SH+ICME category followed by SH+MC, MC and finally CIR. Since the most intense storms were either caused by SH+ICME or SH+MC while the least intense storms were caused by CIR, consequently the correlation was strongest with SH+ICME and SH+MC and least with CIR.