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The formation of Middle Tropospheric Cyclones (MTCs) that are responsible for a large portion of annual precipitation and extreme rainfall events over western India is studied using an unsupervised machine learning algorithm and cyclone…

Atmospheric and Oceanic Physics · Physics 2023-08-16 Pradeep Kushwaha , Jai Sukhatme , Ravi S. Nanjundiah

Using the polar vector magnetic field data observed by Hinode from 2012 to 2021, we study the long-term variations of the magnetic flux, the flux proportion of different polarities, and the magnetic inclination with respect to the local…

Solar and Stellar Astrophysics · Physics 2025-09-25 Shuhong Yang , Chunlan Jin , Qiao Song , Yuzong Zhang , Yin Li , Yijun Hou , Ting Li , Guiping Zhou , Yuanyong Deng , Jingxiu Wang

The 11-year cycle of solar activity follows Hale's law by reversing the magnetic polarity of leading and following sunspots in bipolar regions during the minima of activity. In the 1996-97 solar minimum, most solar activity emerged in…

Astrophysics · Physics 2009-10-31 E. E. Benevolenskaya , J. T. Hoeksema , A. G. Kosovichev , P. H. Scherrer

Using a 3D non-linear mean-field solar dynamo model, we investigate the magnetic helicity flux and magnetic twist, and tilt parameters of bipolar magnetic regions (BMRs) emerging from the solar convection zone due to the magnetic buoyancy…

Solar and Stellar Astrophysics · Physics 2025-08-04 V. V. Pipin , Shangbin Yang , A. G. Kosovichev

Interactions between flows and magnetic fields in the Sun's plasma can change surface waves and flows near active regions, are evident in cyclic changes of large-scale phenomena such as the meridional circulation, and contribute to dynamics…

Solar and Stellar Astrophysics · Physics 2013-09-23 E. J. Zita , C. Smith , N. E. Hurlburt

The solar mean magnetic field (SMMF) is referred to as the disc-averaged line-of-sight (LOS) magnetic field that also reflects the polarity imbalance of the magnetic field on the Sun. The origin of the SMMF has been debated over the past…

Solar and Stellar Astrophysics · Physics 2018-08-13 Souvik Bose , K. Nagaraju

Solar active regions and the processes that occur in them have been extensively studied and analyzed and many types of models and characterizations have been proposed for the occurrence of different eruptive events that take place in the…

Solar and Stellar Astrophysics · Physics 2020-12-09 N. Granados Hernández , S. Vargas Domínguez

Stellar winds are believed to be the dominant factor in spin down of stars over time. However, stellar winds of solar analogs are poorly constrained due to the challenges in observing them. A great improvement has been made in the last…

Solar and Stellar Astrophysics · Physics 2015-06-17 Ofer Cohen , Jeremy J. Drake

The present study examines the response of the terrestrial magnetosphere to the long-term steady declining trends observed in solar magnetic fields and solar wind micro-turbulence levels since mid-1990's that has been continuing beyond the…

Solar and Stellar Astrophysics · Physics 2019-08-08 M. Ingale , P. Janardhan , S. K. Bisoi

Efforts to understand unusual weather or abrupt changes in climate have been plagued by deficiencies of the standard solar model (SSM). While it assumes that our primary source of energy began as a homogeneous ball of hydrogen (H) with a…

Astrophysics · Physics 2007-05-23 O. Manuel , B. W. Ninham , S. E. Friberg

The distribution of magnetic fields of positive and negative polarities over the surface of the Sun was studied. Synoptic maps of the photospheric magnetic field (NSO Kitt Peak, 1978--2016) were used for the analysis. In the time-latitude…

Solar and Stellar Astrophysics · Physics 2022-06-20 E. S. Vernova , M. I. Tyasto , D. G. Baranov

We investigate the evolution of both normal and inverse CMEs ejected at different initial velocities, and observe the effect of the background wind density and their magnetic polarity on their evolution up to 1 AU. We performed 2.5D…

Solar and Stellar Astrophysics · Physics 2019-10-11 S. Hosteaux , E. Chané , S. Poedts

Magnetic quenching of turbulent thermal diffusivity leads to instability of the large-scale field with the production of spatially isolated regions of enhanced field. This conclusion follows from a linear stability analysis in the framework…

Solar and Stellar Astrophysics · Physics 2019-05-01 Leonid L. Kitchatinov

The strength of the radial component of the interplanetary magnetic field (IMF), which is a measure of the Sun's total open flux, is observed to vary by roughly a factor of two over the 11 yr solar cycle. Several recent studies have…

Solar and Stellar Astrophysics · Physics 2021-04-16 Y. -M. Wang , N. R. Sheeley

The magnetic field of the Sun is generated by internal dynamo process with a cyclic period of 11 years or a 22 year magnetic cycle. The signatures of the Sun's magnetic cycle are observed in the different layers of its atmosphere and in its…

Solar and Stellar Astrophysics · Physics 2023-09-26 Sandra V. Jeffers , Rene Kiefer , Travis S. Metcalfe

We explore the cause of the solar cycle variabilities using a novel 3D Babcock--Leighton dynamo model. In this model, based on the toroidal flux at the base of the convection zone, bipolar magnetic regions (BMRs) are produced with…

Solar and Stellar Astrophysics · Physics 2019-01-30 Bidya Binay Karak , Mark Miesch

A key component of solar interior dynamics is the meridional circulation (MC), whose poleward component in the surface layers has been well observed. Time-distance helioseismic studies of the deep structure of MC, however, have yielded…

Solar and Stellar Astrophysics · Physics 2021-01-20 S. P. Rajaguru , H. M. Antia

In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle. Almost eighty years later, Hale described the nature of the Sun's magnetic…

We review recent insights into the dynamics of the solar convection zone obtained from global numerical simulations, focusing on two recent developments in particular. The first is quasi-cyclic magnetic activity in a long-duration dynamo…

Solar and Stellar Astrophysics · Physics 2015-05-20 Mark S. Miesch , Benjamin P. Brown , Matthew K. Browning , Allan Sacha Brun , Juri Toomre

Geomagnetic activity in each phase of the solar cycle consists of 3 parts: (1) a floor below which the geomagnetic activity cannot fall even in the absence of sunspots, related to moderate graduate commencement storms; (2) sunspot-related…

Earth and Planetary Astrophysics · Physics 2015-06-16 B. Kirov , V. N. Obridko , K. Georgieva , E. V. Nepomnyashtaya , B. D. Shelting