A5061747330- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Geophysical and Geoelectrical Methods
- Stellar, planetary, and galactic studies
- Space Science and Extraterrestrial Life
- Space Satellite Systems and Control
- Space exploration and regulation
- Energy Load and Power Forecasting
- Computational Physics and Python Applications
- Meteorological Phenomena and Simulations
- Spacecraft Design and Technology
- Complex Systems and Time Series Analysis
- Climate variability and models
- Lightning and Electromagnetic Phenomena
- Radioactivity and Radon Measurements
- COVID-19 impact on air quality
- COVID-19 epidemiological studies
Vikram Sarabhai Space Centre
2020-2025
Indian Space Research Organisation
2023
University Corporation for Atmospheric Research
2018-2021
Heliophysics
2018-2021
Goddard Space Flight Center
2018-2021
University of America
2020-2021
Catholic University of America
2020-2021
Geological Survey of India
2013-2019
University of Mumbai
2011
While the Sun is generally more eruptive during its maximum and declining phases, observational evidence shows certain cases of powerful solar eruptions quiet phase activity. Occurring in weak Solar Cycle 14 just after minimum, extreme space weather event 1903 October -- November was one these cases. Here, we reconstruct time series geomagnetic activity based on contemporary records. With mid-latitude magnetograms, magnetic storm thought to be caused by a fast coronal mass ejection (~1500...
The Carrington storm in 1859 September has been arguably identified as the greatest geomagnetic ever recorded. However, its exact magnitude and chronology remain controversial, while their source data have derived from Colaba H magnetometer. Here, we located yearbook, containing hourly measurements spot measurements. We reconstructed disturbances horizontal component ({\Delta}H), eastward ({\Delta}Y), vertical ({\Delta}Z) around time of storm. On basis, chronologically revised ICME transit...
Artificial Neural Network (ANN) has proven to be very successful in forecasting a variety of irregular magnetospheric/ionospheric processes like geomagnetic storms and substorms. SYMH ASYH indices represent longitudinal symmetric the asymmetric component ring current. Here, an attempt is made develop prediction model for these using ANN. The current state depends on its past conditions therefore, it necessary consider history prediction. To account this effect Nonlinear Autoregressive with...
The forecasting of local GIC effects has largely relied on the dB/dt as a proxy and, to date, little attention been paid directly geoelectric field or GICs themselves. We approach this problem with machine learning tools, specifically recurrent neural networks LSTMs by taking solar wind observations input and training models predict two different kinds output: first, components Ex Ey; second, in specific substations Austria. is carried out modelled from 26 years one-minute geomagnetic...
Abstract The 2024 May 10 space weather event stands out as the most powerful storm recorded during current solar cycle. This study employs a numerical framework utilizing semiempirical coronal model, along with heliospheric upwind extrapolation time dependence and cone mass ejection (CME) models for inner heliosphere, to forecast wind velocity arrival of CMEs associated this event. simulations were also carried using Space Weather Adaptive Simulation drag-based model (DBM) complex multiple...
We investigated the pulsating aurora observed on 7 January 2014, by a narrow field-of-view (FOV) high-time resolution ground-based white-light imager and all-sky low-time-resolution operated at Poker Flat, AK (geographic: 65.1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1"><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:math> N, 147.4 id="m2"><mml:mrow><mml:mo>°</mml:mo></mml:mrow></mml:math> W). The showed very notable characteristics, such as frequency drift in their...
The signatures of abrupt turnings the vertical component interplanetary magnetic field (IMF), Bz, can be seen at equatorial latitudes through prompt transmission high‐latitude electric fields to lower latitudes, called as penetration (PPE). present work studies PPE in daytime electrojet (EEJ) index derived Indian sector during 2001–2005. are observed polar (PCN index) and (EEJ ionosphere almost instantaneously (<1 min). communication time 12±6 min is between bow shock nose ionosphere, it...
Abstract Understanding extreme space weather events is of paramount importance in efforts to protect technological systems and on the ground. Particularly thermosphere, subsequent magnetic storms can pose serious threats low Earth orbit (LEO) spacecraft by intensifying errors predictions. Extreme (minimum Dst ≤ − 250 nT) are extremely rare: Only seven occurred during era with high‐level accelerometers such as CHAMP (CHAllenge Minisatellite Payload) GRACE (Gravity Recovery And Climate...
We have studied Forbush decrease (FD) event occurred on February 14, 1978 using 43 neutron monitor observatories to understand the global signature of FD. rigidity dependence shock amplitude and total FD amplitude. found almost same power law index for both phase Local time variation maximum depression been investigated which indicate possible effect shock/CME orientation. analyzed constants two recovery. Time slow component recovery show implies diffusion. Solar wind speed was observed be...
ABSTRACT Major solar eruptions occasionally cause magnetic superstorms on the Earth. Despite their serious consequences, low frequency of occurrence provides us with only limited cases through modern instrumental observations, and intensities historical storms before coverage Dst index have been sporadically estimated. Herein, we examine a solar-terrestrial storm that occurred in 1946 March quantitatively evaluate its parameters. During ascending phase Solar Cycle 18, two moderate sunspot...
ABSTRACT In late 1940 March, at least five significant solar flares were reported. They likely launched interplanetary coronal mass ejections (ICMEs), and associated with one of the largest storm sudden commencements (SSCs) since 1868, resulting in space weather hazards that would have societal impacts should it occur today. The initial activity is a proton event. Afterwards, another flare was reported eastern quadrant (N12 E37-38) 11:30–12:30 ut on March 23, magnetic crochets (up to ≈ |80|...
Abstract A Forbush decrease is a sudden in cosmic-ray intensity caused by transient interplanetary disturbances. The substructure of an counterpart coronal mass ejection (ICME) such as shock sheath and/or magnetic cloud independently contributes to decrease, which evident two-step decrease. Our earlier work has shown multistep and recovery within the ICME-driven shock-sheath region. Further, we have suggested that presence small-scale flux rope region causes steady/gradual intensity. Here,...
We study 50 cosmic ray Forbush decreases (FDs) from the Oulu neutron monitor data during 1997-2005 that were associated with Earth-directed interplanetary coronal mass ejections (ICMEs). Such events are generally thought to arise due shielding of rays by a propagating diffusive barrier. The main processes at work diffusion across large-scale magnetic fields carried ICME and their advection solar wind. In an attempt better understand relative importance these effects, we analyse relationship...
Interplanetary coronal mass ejections (ICME) are large-scale eruptions from the Sun and prominent drivers of space weather disturbances, especially intense/extreme geomagnetic storms. Recent studies by our group showed that ICME sheaths and/or magnetic clouds (MC) could be transformed into a planar structure (PMS) speculate these structures might more geo-effective. Thus, we statistically investigated geo-effectiveness non-planar MC regions. We analyzed 420 events observed 1998 to 2017,...