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Browsing by Author "Sundararaman, K"

Browsing by Author "Sundararaman, K"

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  • Dangerous Face of the Sun 
    Sundararaman, K (NISCAIR-CSIR, India, 2010-11)
    Are we going to be roasted alive by killer solar storms that may arrive during the next solar maximum in 2012? Why and how do these solar flares occur and how do they affect the earth? Read on to find out
  • Detection of Short-Period Coronal Oscillations during the Total Solar Eclipse of 24 October, 1995 
    Singh, J; Cowsik, R; Raveendran, A. V; Bagare, S. P; Saxena, A. K; Sundararaman, K; Krishan, V; Naidu, N; Samson, J. P. A; Gabriel, F (Springer, 1997-02)
    An experiment to search for short-period oscillations in the solar corona was conducted during the total solar eclipse of 1995 October 24 at Kalpi, India. The intensity in the continuum, centred around 5500 Å and with a ...
  • Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening 
    Sundararaman, K; Ramesh, K. B; Selvendran, R; Aleem, P. S. M; Hiremath, K. M (Indian Academy of Sciences, 2000-12)
  • Evershed velocities in bipolar sunspots 
    Sundararaman, K; Aleem, P. S. M; Thiagarajan, R (Astronomical Society of India, 1999)
    Spectra taken at the solar telescope-spectrograph, Kodaikanal, are analysed to find the sight-line velocity values in the regions between the opposite polarity sunspots. Velocities in opposite directions in the range 1 - ...
  • Evolution of the active region NOAA 10570 associated with the flares 
    Sundararaman, K; Ramesh, K. B; Selvendran, R (Anita Publications, 2004-12)
    The structure and evolution of the photospheric magnetic fields observed in the active region NOAA 10570 are analyzed using Kodaikanal photoheliogram and spectroheliogram data. It is attempted to evaluate the shear angle ...
  • Filament activity in a quiet region flare 
    Sundararaman, K; Gupta, S. S; Selvendran, R (Indian Academy of Sciences, 1993-03)
    We have taken the case of a circular H-alpha filament observed on May 9, 1979 erupting into a double-ribbon flare associated with a nonspot region. The plage motions are responsible for the filament reorientation and, here ...
  • H-alpha flare of 14 March, 1984 -- Evidence for reconnection? 
    Sundararaman, K; Aleem, S. M; Singh, J; Selvendran, R; Thiagarajan, R (Springer, 1994-01)
    Kodaikanal H-alpha monochromatic and white-light observations are used to study the circular flare of 14 March, 1984. We report here the dynamic activity of the H-alpha filament, which attained a severe twist before erupting ...
  • On the triggering of a spotless double-ribbon flare 
    Rausaria, R. R; Aleem, S. M; Sundararaman, K (Springer Netherlands, 1992-11)
    We have studied the evolution of the double-ribbon, spotless flare of 21 February, 1992, using Kodaikanal Hagr and Kf1 observations. The analysis of the data shows that the Hagr filament underwent a large change in shear ...
  • On the triggering of quiet region flares without filament activation 
    Sundararaman, K; Selvendran, R (Astronomical Society of India, 1997)
    Using Kodaikanal Observations we have analysed the cases of quiet region flares which are not associated with any filament activation. The rotations of the plages play a major role in triggering these spotless flares. The ...
  • The role of sunspot umbral rotation in triggering solar flares 
    Sundararaman, K; Ramesh, K. B; Selvendran, R (Astronomical Society of India, 2003)
    The evolution of large active regions NOAA 9393 and NOAA 9433 observed during March and April 2001 respectively on their successive rotation and the active region NOAA 10069 that appeared during August 2002 were studied. ...
  • Solar variability in the CaII K during solar cycles 21 and 22 
    Sivaraman, K. R; Gupta, S. S; Kariyappa, R; Aleem, P. S. M; Sundararaman, K (Astronomical Society of India, 1993)
    We have monitored the sun in the light of the CaII K line and obtained the disc integrated profiles for the years 1974-91. From these profiles we have estimated the variability of the sun as a star as seen in the various ...
  • Solar X-Ray Spectral Irradiance Variability 
    Ramesh, K. B; Sundararaman, K (Springer, 2006-04)
    Solar spectral irradiance at X-ray wavelengths show large variations over a period of solar cycle. We use X-ray irradiance data in three narrow spectral regimes deduced from Yohkoh SXT measurements to study coronal irradiance ...
  • Space Weather – Sun Earth Relations 
    Sundararaman, K (Scientific Research Publishing, 2011-03)
    Sun, a star of spectral type G2 is the main source of energy to the Earth. Being close to the Earth, Sun pro-duces a resolvable disk of great detail, which is not possible for other stars. Solar flares and coronal mass ...
  • Spot and filament rotation in a sigmoidal flare 
    Sundararaman, K; Ramesh, K. B; Selvendran, R (Astronomical Society of India, 2001)
    The role played by the rotation of the umbrae in a sunspot with respect to the H? filament in inducing magnetic shear for the sigmoidal brightening is reported in this paper. We carried out these studies by using photoheliogram ...
  • Studies on Dynamics of Active Regions and Sunspots 
    Sundararaman, K (Indian Institute of Astrophysics, Bangalore, 1997-10)
  • Sun-Our fascinating star 
    Sundararaman, K (Science Park Publications, 2011-11)
  • Sunspot Motions Associated with Flares 
    Sundararaman, K; Selvendran, R; Thiagarajan, R (Kluwer Academic Publishers, 1998-06)
    The evolution of five bipolar sunspot groups during their disk passage leading to flares are analysed and studied using Kodaikanal Observatory photoheliogram and spectroheliogram data. The changes in the orientation angle ...

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