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Height of Shock Formation in the Solar Corona Inferred from Observations of Type II Radio Bursts and Coronal Mass Ejections
- N. Gopalswamy, H. Xie, D. Choudhary
- Physics
- 5 January 2013
Sunspot Group Decay
- D. Hathaway, D. Choudhary
- Physics
- 14 July 2008
We examine daily records of sunspot group areas (measured in millionths of a solar hemisphere or μHem) for the last 130 years to determine the rate of decay of sunspot group areas. We exclude…
SUCCESSIVE SOLAR FLARES AND CORONAL MASS EJECTIONS ON 2005 SEPTEMBER 13 FROM NOAA AR 10808
- Chang Liu, Jeongwoo Lee, M. Karlický, D. Choudhary, N. Deng, Haimin Wang
- Physics
- 4 August 2009
We present a multiwavelength study of the 2005 September 13 eruption from NOAA AR 10808 that produced total four flares and two fast coronal mass ejections (CMEs) within ∼1.5 hr. Our primary…
A STUDY OF THE HEMISPHERIC ASYMMETRY OF SUNSPOT AREA DURING SOLAR CYCLES 23 AND 24
- P. Chowdhury, D. Choudhary, S. Gosain
- Physics
- 26 April 2013
Solar activity indices vary over the Sun's disk, and various activity parameters are not considered to be symmetric between the northern and southern hemispheres of the Sun. The north–south asymmetry…
Short-term periodicities in interplanetary, geomagnetic and solar phenomena during solar cycle 24
- P. Chowdhury, D. Choudhary, S. Gosain, Y. Moon
- Physics
- 1 March 2015
In this paper we study the quasi-periodic variations of sunspot area/number, 10.7 cm solar radio flux, Average Photospheric Magnetic Flux, interplanetary magnetic field (Bz) and the geomagnetic…
Multiheight Properties of Moving Magnetic Features
- D. Choudhary, K. Balasubramaniam
- Physics
- 1 August 2007
We report on spectropolarimetric and dynamical properties of a moving magnetic feature (MMF) around a disk-center sunspot observed using photospheric (Fe I λλ6301.5 and 6302.5) and lower…
A Practical Approach to Coronal Magnetic Field Extrapolation Based on the Principle of Minimum Dissipation Rate
- Q. Hu, B. Dasgupta, D. Choudhary, J. Büchner
- Physics
- 8 November 2007
We present a newly developed approach to solar coronal magnetic field extrapolation from vector magnetograms, based on the principle of minimum dissipation rate (MDR). The MDR system was derived from…
Statistical Investigation of Supersonic Downflows in the Transition Region above Sunspots
- T. Samanta, H. Tian, D. Choudhary
- PhysicsThe Astrophysical Journal
- 13 April 2018
Downflows at supersonic speeds have been observed in the transition region (TR) above sunspots for more than three decades. These downflows are often seen in different TR spectral lines above…
Flow Field Evolution of a Decaying Sunspot
- N. Deng, D. Choudhary, A. Tritschler, C. Denker, Chang Liu, Haimin Wang
- Physics
- 21 September 2007
We study the evolution of the flows and horizontal proper motions in and around a decaying follower sunspot based on time sequences of two-dimensional spectroscopic observations in the visible and…
Different Periodicities in the Sunspot Area and the Occurrence of Solar Flares and Coronal Mass Ejections in Solar Cycle 23 – 24
- D. Choudhary, J. Lawrence, M. Norris, A. Cadavid
- Physics
- 1 February 2014
In order to investigate the relationship between magnetic-flux emergence, solar flares, and coronal mass ejections (CMEs), we study the periodicity in the time series of these quantities. It has been…
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