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Papers by PRASANNA SUBRAMANIAN

Research paper thumbnail of Kinematics of Strongly Accelerated and Strongly Decelerated DH-type II Associated CMEs

Central European Astrophysical Bulletin, 2013

Research paper thumbnail of Multi-wavelength study of a flare and burst associated coronal mass ejection

The present study consists of the radio emissions observed on 15 May 2013 by ground based and spa... more The present study consists of the radio emissions observed on 15 May 2013 by ground based and space based radio observations. An intensive solar X-ray flare from the location N12E64 was associated with a halo coronal mass ejection (CME) of speed 1366 km/s observed in white light by Solar and Heliospheric Observatory (SOHO)/Large Angle Spectrometric Coronagraph (LASCO) coronagraph. Metric type II and IV radio emission were detected by Culgoora and Bruny island radio spectrograph (BIRS) after flare onset. Also, decameter-hectometric (DH) type II radio burst was detected by wind/radio and plasma wave experiment (WAVES). The low frequency radio signature was found to be generated between 8-42 Ro (Ro = one solar radius). From the analysis, both the high and low frequency type II radio signatures seem to be generated due to shock driven by the CME. This CME was also associated with SEP, IP shock and geomagnetic storm.

Research paper thumbnail of Comparison of ICME Parameters Using Drag Based Model for Interacting and Non-interacting CMEs

It is well known that solar wind drag is an important parameter for propagation of CMEs in the in... more It is well known that solar wind drag is an important parameter for propagation of CMEs in the interplanetary space. In the present work, we utilize the Drag Based Model (DBM) developed recently by Vršnak et al., (2013) to obtain the travel time of CMEs from the Sun to the Earth and speed of interplanetary CME (ICME) near the Earth using the initial parameters of CMEs near the Sun. For this study, we consider the list of 91 CME-ICME pairs given by Manoharan et al., (2004). These events were observed during the period 1997-2002 and the list includes 66 non-interacting and 25 interacting events. The aim of this study is to compare the observed parameters of CMEs/ICMEs (transit time of CMEs and speed of ICMEs) in interacting and non-interacting events with the parameters derived from the DBM. The results obtained from this analysis are: (i) The CME transit times and ICME speeds derived from the model are nearly consistent with the observations for non-interacting CMEs (correlation coef...

Research paper thumbnail of Investigations of slow and fast coronal mass ejections and their associated activities in Solar cycle 24

Intensive flare (>M5.0 X-ray class) associated Coronal Mass Ejections (CMEs), during 2008- 201... more Intensive flare (>M5.0 X-ray class) associated Coronal Mass Ejections (CMEs), during 2008- 2013 in solar cycle 24, are separated into two groups based on CME speed. Group-I contains 31 CME events with speed below 900 km/s and Group-II contains 27 CME events with speed above 900 km/s. (i) The mean CME speeds of Groups I and II are found to be 558 km/s and 1629 km/s, and the mean CME width of the Group-II is slightly higher than the Group-I. The CMEs of Group-II are highly decelerated than the CMEs of Group-I. (ii) The rise time and duration of intensive flares of Group-II is slightly greater than those of Group-I. (iii) While 60% of Group-I events are located on the southern hemisphere, 85% of Group-II events are located on the northern hemisphere. (iv) The number of Halos, DH type IIs, SEP events associated with Group-II are respectively 2, 3 and 6 times that of Group-I. (v) Utilizing the density models of suitably connecting the corona and interplanetary medium, the shock...

Research paper thumbnail of A Study on the Kinematics of a Cme-Shock Interaction Event Associated with Flares and Type II Bursts on 22 May 2013

The subject of interaction between Corona Mass Ejections (CMEs) is important in the concept of sp... more The subject of interaction between Corona Mass Ejections (CMEs) is important in the concept of space-weather studies. In this paper, we study a CME-CME interaction event on 22 May 2013 observed by coronagraphs on board SOHO and STEREO. At first, a C-class X-ray flare occurred at 8:02 UT at the location N21W89. At 8:48 UT, a slow pre-CME of speed = 687 km/s was observed by C2 coronagraph. At 13:08 UT, an M-class X-ray flare was detected by GOES spacecraft from the location N13W80. It was associated with a fast and wide CME. This primary CME having speed = 1466 km/s was associated with a DH type II radio burst. The interaction between pre-CME trailing edge and shock of primary CME at PA 43◦ at height ∼11–15 Ro was found using STEREO COR-2 data. The expansion and radial speed of the shock of primary CME was found to be 1870 km/s and 1515 km/s, respectively. A broad-band type II was observed in radio spectrum in the frequency range 2 – 0.3 MHz. The kinematic profiles of preand primary C...

Research paper thumbnail of MAX PLANK quotes in Tamil

Research paper thumbnail of COVID-19 and EEG Technology

Corona Virus is a fast spreading virus affected lot of people. Still no solutions are available t... more Corona Virus is a fast spreading virus affected lot of people. Still no solutions are available to control them. Lot of countries are taking steps for the affected people. Some recent statistics suggests that Corona virus is a adult virus. If so, how we use that as a tool to control by our brain frequency scaling. This article deals with how EEG can help for solving Corona virus treatments.

Research paper thumbnail of Beta decay and Neutrinos impact on cosmic weather

unpublished, 2020

The sunspot cycle affects space weather condition within the solar system. The cosmic ray weathe... more The sunspot cycle affects space weather condition within the solar system. The cosmic ray weather is primarily dominated by cosmic particles. When high energy particles encounters interaction with Earth atmosphere, the shower activity scatters large number of high energy particles along with neutrinos for large areas. Laser based Interferometer of detecting Gravitational Wave Observatory (LIGO) detected some gravitational wave (GW) activity during 2015-2017. The aim of the present study is to know the influence of gravitational waves, neutrinos in cosmic ray weather at Earth. The study finds that cosmic ray weather severely affected due to GW activities in 2017. Large increase in cosmic ray intensity suggests that large increase of muon particle generation in the atmosphere of Earth. The astronomical radio activity in neutron stars, pulsars etc. are a kind of beta decay activity which is due to Fermi’s interaction.

Research paper thumbnail of Multiwavelength Analysis of the Kinematics of a Long Duration Flare-CME Event on 27 January 2012

Research paper thumbnail of Study of Interplanetary CMEs/Shocks During Solar Cycle 24 Using Drag-Based Model: The Role of Solar Wind

Research paper thumbnail of Study of intensive solar flares in the rise phase of solar cycle 23 and 24 and other activities

Astrophysics and Space Science

Research paper thumbnail of Interaction Between Two CMEs During 14 – 15 February 2011 and Their Unusual Radio Signature

Solar Physics, 2014

ABSTRACT

Research paper thumbnail of Interacting CMEs and their associated flare and SEP activities

Astrophysics and Space Science, 2014

We have analyzed a set of 25 interacting events which are associated with the DH type II bursts. ... more We have analyzed a set of 25 interacting events which are associated with the DH type II bursts. These events are selected from the Coronal Mass Ejections (CMEs) observed during the period 1997-2010 in SOHO/LASCO and DH type IIs observed in Wind/WAVES. Their pre and primary CMEs from nearby active regions are identified using SOHO/LASCO and EIT images and their height-time diagrams. Their interacting time and height are obtained, and their associated activities, such as, flares and Solar Energetic Particles(>10 pfu) are also investigated. Results from the analysis are: primary CMEs are much faster than the pre-CMEs, their X-ray flares are also stronger (X and M class) compared to the flares (C and M class) of pre-CMEs. Most of the events (22/25) occurred during the period 2000-2006. From the observed width and speed of pre and primary CMEs, it is found that the pre-CMEs are found to be less energetic than the primary CMEs. While the primary CMEs are tracked up to the end of LASCO field of view (30Rs), most of the pre-CMEs can be tracked up to <26 Rs. The SEP intensity is found to be related with the integrated flux of X-ray flares associated with the primary CMEs for nine events originating from the western region.

Research paper thumbnail of Study of interacting CMEs and DH type II radio bursts

Astrophysics and Space Science, 2013

ABSTRACT

Research paper thumbnail of Experimental f ″of As at 170, 200, 250 and 300 K from the Bijvoet pairs of GaAs

Anomalous dispersion effects lead to the modification of the measured X-ray structure factors. In... more Anomalous dispersion effects lead to the modification of the measured X-ray structure factors. In this work, we have determined the imaginary part of the anomalous dispersion correction terms (f″ ″) of arsenide atom (As), through the X-ray data collected using spherical single crystal of GaAs, at various temperatures, i.e. 170, 200, 250 and 300 K. It is stressed that more measurements of f″ ″ of the elements are needed to confirm the theoretical calculations.

Research paper thumbnail of Kinematics of Strongly Accelerated and Strongly Decelerated DH-type II Associated CMEs

Central European Astrophysical Bulletin, 2013

Research paper thumbnail of Multi-wavelength study of a flare and burst associated coronal mass ejection

The present study consists of the radio emissions observed on 15 May 2013 by ground based and spa... more The present study consists of the radio emissions observed on 15 May 2013 by ground based and space based radio observations. An intensive solar X-ray flare from the location N12E64 was associated with a halo coronal mass ejection (CME) of speed 1366 km/s observed in white light by Solar and Heliospheric Observatory (SOHO)/Large Angle Spectrometric Coronagraph (LASCO) coronagraph. Metric type II and IV radio emission were detected by Culgoora and Bruny island radio spectrograph (BIRS) after flare onset. Also, decameter-hectometric (DH) type II radio burst was detected by wind/radio and plasma wave experiment (WAVES). The low frequency radio signature was found to be generated between 8-42 Ro (Ro = one solar radius). From the analysis, both the high and low frequency type II radio signatures seem to be generated due to shock driven by the CME. This CME was also associated with SEP, IP shock and geomagnetic storm.

Research paper thumbnail of Comparison of ICME Parameters Using Drag Based Model for Interacting and Non-interacting CMEs

It is well known that solar wind drag is an important parameter for propagation of CMEs in the in... more It is well known that solar wind drag is an important parameter for propagation of CMEs in the interplanetary space. In the present work, we utilize the Drag Based Model (DBM) developed recently by Vršnak et al., (2013) to obtain the travel time of CMEs from the Sun to the Earth and speed of interplanetary CME (ICME) near the Earth using the initial parameters of CMEs near the Sun. For this study, we consider the list of 91 CME-ICME pairs given by Manoharan et al., (2004). These events were observed during the period 1997-2002 and the list includes 66 non-interacting and 25 interacting events. The aim of this study is to compare the observed parameters of CMEs/ICMEs (transit time of CMEs and speed of ICMEs) in interacting and non-interacting events with the parameters derived from the DBM. The results obtained from this analysis are: (i) The CME transit times and ICME speeds derived from the model are nearly consistent with the observations for non-interacting CMEs (correlation coef...

Research paper thumbnail of Investigations of slow and fast coronal mass ejections and their associated activities in Solar cycle 24

Intensive flare (>M5.0 X-ray class) associated Coronal Mass Ejections (CMEs), during 2008- 201... more Intensive flare (>M5.0 X-ray class) associated Coronal Mass Ejections (CMEs), during 2008- 2013 in solar cycle 24, are separated into two groups based on CME speed. Group-I contains 31 CME events with speed below 900 km/s and Group-II contains 27 CME events with speed above 900 km/s. (i) The mean CME speeds of Groups I and II are found to be 558 km/s and 1629 km/s, and the mean CME width of the Group-II is slightly higher than the Group-I. The CMEs of Group-II are highly decelerated than the CMEs of Group-I. (ii) The rise time and duration of intensive flares of Group-II is slightly greater than those of Group-I. (iii) While 60% of Group-I events are located on the southern hemisphere, 85% of Group-II events are located on the northern hemisphere. (iv) The number of Halos, DH type IIs, SEP events associated with Group-II are respectively 2, 3 and 6 times that of Group-I. (v) Utilizing the density models of suitably connecting the corona and interplanetary medium, the shock...

Research paper thumbnail of A Study on the Kinematics of a Cme-Shock Interaction Event Associated with Flares and Type II Bursts on 22 May 2013

The subject of interaction between Corona Mass Ejections (CMEs) is important in the concept of sp... more The subject of interaction between Corona Mass Ejections (CMEs) is important in the concept of space-weather studies. In this paper, we study a CME-CME interaction event on 22 May 2013 observed by coronagraphs on board SOHO and STEREO. At first, a C-class X-ray flare occurred at 8:02 UT at the location N21W89. At 8:48 UT, a slow pre-CME of speed = 687 km/s was observed by C2 coronagraph. At 13:08 UT, an M-class X-ray flare was detected by GOES spacecraft from the location N13W80. It was associated with a fast and wide CME. This primary CME having speed = 1466 km/s was associated with a DH type II radio burst. The interaction between pre-CME trailing edge and shock of primary CME at PA 43◦ at height ∼11–15 Ro was found using STEREO COR-2 data. The expansion and radial speed of the shock of primary CME was found to be 1870 km/s and 1515 km/s, respectively. A broad-band type II was observed in radio spectrum in the frequency range 2 – 0.3 MHz. The kinematic profiles of preand primary C...

Research paper thumbnail of MAX PLANK quotes in Tamil

Research paper thumbnail of COVID-19 and EEG Technology

Corona Virus is a fast spreading virus affected lot of people. Still no solutions are available t... more Corona Virus is a fast spreading virus affected lot of people. Still no solutions are available to control them. Lot of countries are taking steps for the affected people. Some recent statistics suggests that Corona virus is a adult virus. If so, how we use that as a tool to control by our brain frequency scaling. This article deals with how EEG can help for solving Corona virus treatments.

Research paper thumbnail of Beta decay and Neutrinos impact on cosmic weather

unpublished, 2020

The sunspot cycle affects space weather condition within the solar system. The cosmic ray weathe... more The sunspot cycle affects space weather condition within the solar system. The cosmic ray weather is primarily dominated by cosmic particles. When high energy particles encounters interaction with Earth atmosphere, the shower activity scatters large number of high energy particles along with neutrinos for large areas. Laser based Interferometer of detecting Gravitational Wave Observatory (LIGO) detected some gravitational wave (GW) activity during 2015-2017. The aim of the present study is to know the influence of gravitational waves, neutrinos in cosmic ray weather at Earth. The study finds that cosmic ray weather severely affected due to GW activities in 2017. Large increase in cosmic ray intensity suggests that large increase of muon particle generation in the atmosphere of Earth. The astronomical radio activity in neutron stars, pulsars etc. are a kind of beta decay activity which is due to Fermi’s interaction.

Research paper thumbnail of Multiwavelength Analysis of the Kinematics of a Long Duration Flare-CME Event on 27 January 2012

Research paper thumbnail of Study of Interplanetary CMEs/Shocks During Solar Cycle 24 Using Drag-Based Model: The Role of Solar Wind

Research paper thumbnail of Study of intensive solar flares in the rise phase of solar cycle 23 and 24 and other activities

Astrophysics and Space Science

Research paper thumbnail of Interaction Between Two CMEs During 14 – 15 February 2011 and Their Unusual Radio Signature

Solar Physics, 2014

ABSTRACT

Research paper thumbnail of Interacting CMEs and their associated flare and SEP activities

Astrophysics and Space Science, 2014

We have analyzed a set of 25 interacting events which are associated with the DH type II bursts. ... more We have analyzed a set of 25 interacting events which are associated with the DH type II bursts. These events are selected from the Coronal Mass Ejections (CMEs) observed during the period 1997-2010 in SOHO/LASCO and DH type IIs observed in Wind/WAVES. Their pre and primary CMEs from nearby active regions are identified using SOHO/LASCO and EIT images and their height-time diagrams. Their interacting time and height are obtained, and their associated activities, such as, flares and Solar Energetic Particles(>10 pfu) are also investigated. Results from the analysis are: primary CMEs are much faster than the pre-CMEs, their X-ray flares are also stronger (X and M class) compared to the flares (C and M class) of pre-CMEs. Most of the events (22/25) occurred during the period 2000-2006. From the observed width and speed of pre and primary CMEs, it is found that the pre-CMEs are found to be less energetic than the primary CMEs. While the primary CMEs are tracked up to the end of LASCO field of view (30Rs), most of the pre-CMEs can be tracked up to <26 Rs. The SEP intensity is found to be related with the integrated flux of X-ray flares associated with the primary CMEs for nine events originating from the western region.

Research paper thumbnail of Study of interacting CMEs and DH type II radio bursts

Astrophysics and Space Science, 2013

ABSTRACT

Research paper thumbnail of Experimental f ″of As at 170, 200, 250 and 300 K from the Bijvoet pairs of GaAs

Anomalous dispersion effects lead to the modification of the measured X-ray structure factors. In... more Anomalous dispersion effects lead to the modification of the measured X-ray structure factors. In this work, we have determined the imaginary part of the anomalous dispersion correction terms (f″ ″) of arsenide atom (As), through the X-ray data collected using spherical single crystal of GaAs, at various temperatures, i.e. 170, 200, 250 and 300 K. It is stressed that more measurements of f″ ″ of the elements are needed to confirm the theoretical calculations.