Publications (36)
Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1
Jagdev Singh, R. Ramesh, B. Raghavendra Prasad +21
Aditya-L1, India's first dedicated mission to study the Sun and its atmosphere from the Sun-Earth Lagrangian L1 location was successfully launched on 2023 September 2. It carries s…
Formation and eruption of sigmoidal structure from a weak field region of NOAA 11942
N. Vasantharaju, P. Vemareddy, B. Ravindra +1
Using observations from Solar Dynamics Observatory, we studied an interesting example of a sigmoid formation and eruption from small-scale flux canceling regions of active region (…
Finding the critical decay index in solar prominence eruptions
N. Vasantharaju, P. Vemareddy, B. Ravindra +1
The background field is assumed to play prime role in the erupting structures like prominences. In the flux rope models, the critical decay index () is a measure of the rate a…
Prominence eruption initiated by helical kink-instability of an embedded flux rope
P. Vemareddy, N. Gopalswamy, B. Ravindra
We study the triggering mechanism of a limb-prominence eruption and the associated coronal mass ejection near AR 12342 using SDO and LASCO/SOHO observations. The prominence is seen…
On the Role of Rotating Sunspots in the Activity of Solar Active Region NOAA 11158
P. Vemareddy, A. Ambastha, R. A. Maurya
We study the role of rotating sunspots in relation to the evolution of various physical parameters characterizing the non-potentiality of the active region NOAA 11158 and its erupt…
Filament Eruption in NOAA 11093 Leading to a Two-Ribbon M1 Class Flare and CME
P. Vemareddy, R. A. Maurya, A. Ambastha
We present multi-wavelength analysis of an eruption event that occurred in Active Region (AR) NOAA 11093 on 7 August 2010, using data obtained from SDO, STEREO, RHESSI and GONG H$Î…
Understanding the formation and eruption of sigmoidal structure through data-driven modeling of magnetic evolution in solar active region 13500
P. Vemareddy, S. Nair, S. Gosain
We investigate the magnetic origin of the coronal mass ejection (CME) that occurred on November 28, 2023, at 19:50UT from active region (AR) 13500 located near the solar disk-cente…
Statistical study of magnetic non-potential measures in confined and eruptive flares
N. Vasantharaju, P. Vemareddy, B. Ravindra +1
Using the HMI/SDO vector magnetic field observations, we studied the relation of degree of magnetic non-potentiality with the observed flare/CME in active regions. From a sample of…
Simulating the formation and eruption of flux rope by magneto-friction model driven by time-dependent electric fields
P. Vemareddy
Aiming to capture the formation and eruption of flux ropes (FRs) in the source active regions (ARs), we simulate the coronal magnetic field evolution of the AR 11429 employing the…
Study of Three-Dimensional Magnetic Structure and the Successive Eruptive Nature of Active Region 12371
P. Vemareddy, P. Demóulin
We study the magnetic structure of successively erupting sigmoid in active region 12371 by modeling the quasi-static coronal field evolution with non-linear force-free field (NLFFF…
Eruption of EUV Hot-Channel near Solar Limb and Associated Moving Type-IV Radio Burst
P. Vemareddy, P. Démoulin, K. Sasikumar Raja +3
Using the observations from Solar Dynamics Observatory, we study an eruption of a hot-channel flux rope (FR) near the solar-limb on February 9, 2015. The pre-eruptive structure is…
Very fast helicity injection leading to critically stable state and large eruptive activity in solar active region NOAA 12673
P. Vemareddy
Using the photospheric magnetic and coronal observations of Solar Dynamics Observatory, we studied the build-up and eruption of coronal non-potential magnetic structure in emerging…
Data-driven simulations of magnetic field evolution in Active Region 11429: Magneto-friction method using PENCIL code
P. Vemareddy, Jörn Warnecke, Ph. A. Bourdin
Coronal magnetic fields evolve quasi statically over long time scales and dynamically over short time scales. As of now there exists no regular measurements of coronal magnetic fie…
Magnetic evolution of active regions: formation and eruption of magnetic flux ropes
P. Vemareddy
Magnetic flux ropes (FRs) are twisted structures appearing on the sun, predominantly in the magnetically concentrated regions. These structures appear as coronal features known as…
Data processing of Visible Emission Line Coronagraph Onboard ADITYA L1
Muthu Priyal, Jagdev Singh, B. Raghavendra Prasad +28
ADITYA-L1 is India's first dedicated mission to observe the sun and its atmosphere from a halo orbit around L1 point. Visible emission line coronagraph (VELC) is the prime payload…
Flux Emergence in the Solar Active Region NOAA 11158: The Evolution of Net Current
P. Vemareddy, P. Venkatakrishnan, S. Karthikreddy
We present a detailed investigation on the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from…
Comparison of magnetic properties in a magnetic cloud and its solar source on April 11-14 2013
P. Vemareddy, C. Möstl, T. Rollett +3
In the context of Sun-Earth connection of coronal mass ejections and magnetic flux ropes (MFRs), we studied the solar active region (AR) and the magnetic properties of magnetic clo…
Successive Homologous Coronal Mass Ejections driven by shearing and converging motions in solar active region NOAA 12371
P. Vemareddy
We study magnetic field evolution in AR12371 relating its successive eruptive nature. During the disk transit of seven days, the AR launched four sequential fast coronal mass eject…
Magnetic structure of solar active region NOAA 11158
P. Vemareddy, A. Ambastha, T. Wiegelmann
Magnetic fields in the solar corona are responsible for a wide range of phenomena. However, any direct measurements of the coronal magnetic fields are very difficult due to lack of…
Magnetic Structure in Successively Erupting Active Regions: Comparison of Flare-Ribbons with Quasi-Separatrix Layers
P. Vemareddy
This paper studies the magnetic topology of successively erupting active regions (ARs) 11429 and 12371. Employing vector magnetic field observations from Helioseismic and Magnetic…
Successive Injection of Opposite Magnetic Helicity in Solar Active Region NOAA 11928
P. Vemareddy, P. Démoulin
Understanding the nature and evolution of the photospheric helicity flux transfer is a key to reveal the role of magnetic helicity in coronal dynamics of solar active regions. Usin…
On the injection of helicity by shearing motion of fluxes in relation to Flares and CMEs
P. Vemareddy, A. Ambastha, R. A. Maurya +1
An investigation of helicity injection by photospheric shear motions is carried out for two active regions(ARs), NOAA 11158 and 11166, using line-of-sight magnetic field observatio…
Filament eruption from active region 13283 leading to fast halo-CME and intense geomagnetic storm on 23 April 2023
P. Vemareddy
Using multi-instrument and multi-wavelength observations, we studied a CME eruption that led to intense geomagnetic storm on 23 April 2023. The eruption occurred on April 21 in sol…
Velocity and Magnetic Transients Driven by the X2.2 White-Light Flare of 2011 February 15 in NOAA 11158
R. A. Maurya, P. Vemareddy, A. Ambastha
The first X-class flare of the current solar cycle 24 occurred in Active Region NOAA 11158 during its central meridian passage on 2011 February 15. This two ribbon white-light flar…
An intense geomagnetic storm originated from stealth Coronal Mass Ejection: remote and observations by near radially aligned spacecraft
P. Vemareddy, K. Selva Bharathi
We investigate the solar origin and heliospheric evolution of an intense geomagnetic storm that occurred on March 23-24, 2023. Despite multiple candidate CMEs observed between Marc…
Magnetic imprints of eruptive and non-eruptive Solar flares as observed by Solar Dynamics Observatory
N. Vasantharaju, P. Vemareddy, B. Ravindra +1
The abrupt and permanent changes of photospheric magnetic field in the localized regions of active regions during solar flares called magnetic imprints (MIs), have been observed fo…
Magnetohydrodynamic Simulation of the X9.3 Flare on 2017 September 6: Evolving Magnetic Topology
Chaowei Jiang, Peng Zou, Xueshang Feng +7
Three-dimensional magnetic topology is crucial to understanding the explosive release of magnetic energy in the corona during solar flares. Much attention has been given to the pre…
Quasi-Static 3D-Magnetic Field Evolution in Solar Active Region NOAA 11166 Associated with X1.5 Flare
P. Vemareddy, T. Wiegelmann
We study the quasi-static evolution of coronal magnetic fields constructed from the Non Linear Force Free Field (NLFFF) approximation aiming to understand the relation between the…
Successive Injection of Opposite Magnetic Helicity: Evidence for Active Regions without Coronal Mass Ejections
P. Vemareddy
Magnetic helicity (MH) is a measure of twist and shear of magnetic field. MH is injected in the active region (AR) corona through photospheric footpoint motions causing twisted and…
Nature of helicity injection in non-erupting solar active regions
P. Vemareddy
Using time-sequence vector magnetic field and coronal observations from \textit{Solar Dynamics Observatory}, we report the observations of the magnetic field evolution and coronal…
Initiation and Eruption Process of Magnetic Flux Rope from Solar Active Region NOAA 11719 to Earth Directed-CME
P. Vemareddy, J. Zhang
An eruption event launched from solar active region (AR) NOAA 11719 is investigated based on coronal EUV observations and photospheric magnetic field measurements obtained from Sol…
Formation and Eruption of Filament Channel in Solar Active Region 12975: Insights from Observations and Simulations of Magnetic Field Evolution
Dinesh Mishra, P. Vemareddy, Brajesh Kumar
We studied the magnetic field evolution of active region (AR) 12975 using a time-dependent magnetofrictional (TMF) model. This AR produced two consecutive CMEs associated with M-cl…
The Magnetic Field Geometry of Small Solar Wind Flux Ropes Inferred from their Twist Distribution
W. Yu, C. J. Farrugia, N. Lugaz +4
This work extends recent efforts on the force-free modeling of large flux rope-type structures (magnetic clouds, MCs) to much smaller spatial scales. We first select small flux rop…
Degree of electric current neutralization and the activity in solar Active Regions
P. Vemareddy
Using time-sequence vector magnetic field observation from \textit{Helioseismic and Magnetic Imager}, we examined the connection of non-neutralized currents and the observed activi…
A Full Study on the Sun-Earth Connection of an Earth-Directed CME Magnetic Flux Rope
P. Vemareddy, W. Mishra
We present an investigation of an eruption event of coronal mass ejection (CME) magnetic flux rope (MFR) from source active region (AR) NOAA 11719 on 11 April 2013 utilizing observ…
Sunspot Rotation as a Driver of Major Solar Eruptions in NOAA Active Region 12158
P. Vemareddy, X. Cheng, B. Ravindra
We studied the developing conditions of sigmoid structure under the influence of magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vecto…