suman Garia - Academia.edu (original) (raw)

Papers by suman Garia

Research paper thumbnail of Study of Cosmic Ray Intensity in Relation to the Interplanetary Magnetic Field and Geomagnetic Storms for Solar Cycle 23

Solar Physics, Feb 1, 2016

In the present study, we investigate the association of cosmic ray intensity (CRI) with various s... more In the present study, we investigate the association of cosmic ray intensity (CRI) with various solar wind parameters (i.e. solar wind speed V, plasma proton temperature, plasma proton density), interplanetary magnetic field (IMF B), geomagnetic storms (GSs), averaged planetary A-index (Ap index) and sun spot number (SSN) for the period 2009-2016 (solar cycle 24) by using their daily mean average. To find the association of CRI with various solar wind parameters, GSs, IMF B, Ap index and SSN, we incorporate the analysis technique by superposed-epoch method. We have observed that CRI decreases with the increase in IMF B. Moreover the time-lag analysis has been performed by the method of correlation coefficient and observed a time lag of 0 to 2 day between the decrease in CRI and increase in IMF B. In addition, we show that the CRI is found to decrease in a similar pattern to disturbance storm time (Dst index) for most of the period of solar cycle 24. The high and positive correlation is found between CRI and Dst index. The CRI and Ap index are better anti-correlated to each other than CRI and IMF. CRI and SSN are positively correlated with each other. Solar wind parameters such as solar wind speed V is a CR-effective parameter while plasma proton temperature and plasma proton density are not CReffective parameters. The indicated parameters such as Dst index, Ap index, IMF B and solar wind parameters such as solar wind speed V, plasma proton temperature, plasma proton density shows a kind of irregular variations for solar cycle 23 and 24 while CRI and SSN shows distinct behaviour for the two cycle.

Research paper thumbnail of Association between Geomagnetic Storms and Forbush Decreases

In the present work we have chosen 78 Coronal Mass Ejections (CMEs) events from 1999 to 2005.We h... more In the present work we have chosen 78 Coronal Mass Ejections (CMEs) events from 1999 to 2005.We have done a comparative study to investigate the variation of Cosmic Ray (CR) intensity and geomagnetic activity during the period of seven years. Here we used Disturbance storm time index (Dst) as a measure of geomagnetic disturbance. We observed a significant variation in CR intensity in 2000, 2004 and 2005. We found that halo CMEs and fast Interplanetary Coronal Mass Ejections (ICMEs) are more geo-effective than non-halo CMEs and slower ICMEs but slower ICMEs are found to be more effective in causing FDs in CRs. Keyword Coronal Mass Ejection · Geomagnetic Storm · Disturbance storm time index Forbush Decrease Introduction CMEs produce large disturbances in the solar wind. These disturbances are the primary cause of Geomagnetic Storms (GSs) and Forbush Decreases (FDs). CMEs are the source of major disturbances in the interplanetary medium, which further produce sudden changes in the the ...

Research paper thumbnail of Study of Coronal Mass Ejections in Relation with Geomagnetic Storm and Forbush Decrease in Cosmic Rays

Research paper thumbnail of Solar flares associated coronal mass ejections in case of type II radio bursts

Astrophysics and Space Science, 2016

In this paper, we have selected 114 flare-CME events accompanied with Deca-hectometric (DH) type ... more In this paper, we have selected 114 flare-CME events accompanied with Deca-hectometric (DH) type II radio burst chosen from 1996 to 2008 (i.e., solar cycle 23). Statistical analyses are performed to examine the relationship of flare-CME events accompanied with DH type II radio burst with Interplanetary Magnetic field (IMF), Geomagnetic storms (GSs) and Cosmic Ray Intensity (CRI). The collected sample events are divided into two groups. In the first group, we considered 43 events which lie under the CME span and the second group consists of 71 events which are outside the CME span. Our analysis indicates that flare-CME accompanied with DH type II radio burst is inconsistent with CSHKP flare-CME model. We apply the Chree analysis by the superposed epoch method to both set of data to find the geo-effectiveness. We observed different fluctuations in IMF for arising and decay phase of solar cycle in both the cases. Maximum decrease in Dst during arising and decay phase of solar cycle is different for both the cases. It is noted that when flare lie outside the CME span CRI shows comparatively more variation than the flare lie under the CME span. Furthermore, we found that flare lying under the CME span is more geo effective than the flare outside of CME span. We noticed that the time leg between IMF Peak value and GSs, IMF and CRI is on average one day for both the cases. Also, the time leg between CRI and GSs is on average 0 to 1 day for both the cases. In case flare lie under the CME span we observed high correlation (0.64) between CRI and Dst whereas when flare lie outside the CME span a weak correlation (0.47) exists. Thus, flare position with respect to CME span play a key role for geo-effectiveness of CME.

Research paper thumbnail of Study of Cosmic Ray Intensity in Relation to the Interplanetary Magnetic Field and Geomagnetic Storms for Solar Cycle 23

Solar Physics, Feb 1, 2016

In the present study, we investigate the association of cosmic ray intensity (CRI) with various s... more In the present study, we investigate the association of cosmic ray intensity (CRI) with various solar wind parameters (i.e. solar wind speed V, plasma proton temperature, plasma proton density), interplanetary magnetic field (IMF B), geomagnetic storms (GSs), averaged planetary A-index (Ap index) and sun spot number (SSN) for the period 2009-2016 (solar cycle 24) by using their daily mean average. To find the association of CRI with various solar wind parameters, GSs, IMF B, Ap index and SSN, we incorporate the analysis technique by superposed-epoch method. We have observed that CRI decreases with the increase in IMF B. Moreover the time-lag analysis has been performed by the method of correlation coefficient and observed a time lag of 0 to 2 day between the decrease in CRI and increase in IMF B. In addition, we show that the CRI is found to decrease in a similar pattern to disturbance storm time (Dst index) for most of the period of solar cycle 24. The high and positive correlation is found between CRI and Dst index. The CRI and Ap index are better anti-correlated to each other than CRI and IMF. CRI and SSN are positively correlated with each other. Solar wind parameters such as solar wind speed V is a CR-effective parameter while plasma proton temperature and plasma proton density are not CReffective parameters. The indicated parameters such as Dst index, Ap index, IMF B and solar wind parameters such as solar wind speed V, plasma proton temperature, plasma proton density shows a kind of irregular variations for solar cycle 23 and 24 while CRI and SSN shows distinct behaviour for the two cycle.

Research paper thumbnail of Association between Geomagnetic Storms and Forbush Decreases

In the present work we have chosen 78 Coronal Mass Ejections (CMEs) events from 1999 to 2005.We h... more In the present work we have chosen 78 Coronal Mass Ejections (CMEs) events from 1999 to 2005.We have done a comparative study to investigate the variation of Cosmic Ray (CR) intensity and geomagnetic activity during the period of seven years. Here we used Disturbance storm time index (Dst) as a measure of geomagnetic disturbance. We observed a significant variation in CR intensity in 2000, 2004 and 2005. We found that halo CMEs and fast Interplanetary Coronal Mass Ejections (ICMEs) are more geo-effective than non-halo CMEs and slower ICMEs but slower ICMEs are found to be more effective in causing FDs in CRs. Keyword Coronal Mass Ejection · Geomagnetic Storm · Disturbance storm time index Forbush Decrease Introduction CMEs produce large disturbances in the solar wind. These disturbances are the primary cause of Geomagnetic Storms (GSs) and Forbush Decreases (FDs). CMEs are the source of major disturbances in the interplanetary medium, which further produce sudden changes in the the ...

Research paper thumbnail of Study of Coronal Mass Ejections in Relation with Geomagnetic Storm and Forbush Decrease in Cosmic Rays

Research paper thumbnail of Solar flares associated coronal mass ejections in case of type II radio bursts

Astrophysics and Space Science, 2016

In this paper, we have selected 114 flare-CME events accompanied with Deca-hectometric (DH) type ... more In this paper, we have selected 114 flare-CME events accompanied with Deca-hectometric (DH) type II radio burst chosen from 1996 to 2008 (i.e., solar cycle 23). Statistical analyses are performed to examine the relationship of flare-CME events accompanied with DH type II radio burst with Interplanetary Magnetic field (IMF), Geomagnetic storms (GSs) and Cosmic Ray Intensity (CRI). The collected sample events are divided into two groups. In the first group, we considered 43 events which lie under the CME span and the second group consists of 71 events which are outside the CME span. Our analysis indicates that flare-CME accompanied with DH type II radio burst is inconsistent with CSHKP flare-CME model. We apply the Chree analysis by the superposed epoch method to both set of data to find the geo-effectiveness. We observed different fluctuations in IMF for arising and decay phase of solar cycle in both the cases. Maximum decrease in Dst during arising and decay phase of solar cycle is different for both the cases. It is noted that when flare lie outside the CME span CRI shows comparatively more variation than the flare lie under the CME span. Furthermore, we found that flare lying under the CME span is more geo effective than the flare outside of CME span. We noticed that the time leg between IMF Peak value and GSs, IMF and CRI is on average one day for both the cases. Also, the time leg between CRI and GSs is on average 0 to 1 day for both the cases. In case flare lie under the CME span we observed high correlation (0.64) between CRI and Dst whereas when flare lie outside the CME span a weak correlation (0.47) exists. Thus, flare position with respect to CME span play a key role for geo-effectiveness of CME.