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Browsing by Author "Kariyappa, R"

Browsing by Author "Kariyappa, R"

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  • Bright points in G-Band and Ca IIH images from hinode 
    Pradeep Chitta, L; Kariyappa, R (Springer, 2010)
    We analyze a time sequence simultaneous G-band and Ca IIH images taken with Hinode/SOT on 14 April 2007 during 17:00-18:00UT. In each sequence, we selected 20 bright points and derived their light curves. Power-spectrum ...
  • Broad Band Photometry of the Solar Corona of 1983, June 11 
    Sivaraman, K. R; Singh, J; Kapoor, R. C; Kariyappa, R (Indian Institute of Astrophysics, Bangalore, 1985-11)
    The solar corona was photographed at an effective wavelength of 6300A during the total eclipse of 1983, June 11 at Indonesia. From the isophotes of the corona, the intensity distributions along the equator, poles, streamers ...
  • CA II K Line Profile of the Truly Quiet Sun 
    Sivaraman, K. R; Gupta, S. S; Kariyappa, R (Kluwer Academic Publishers, 1996-01)
    While evaluating the chromospheric variability (solar cycle related or any other) using the Ca II K line (λ3933.684 Å) as an indicator, an essential prerequisite is the knowledge of the profile of a truly quiet Sun in the ...
  • Calibration on the Sun for stellar magnetic fields 
    Sivaraman, K. R; Bagare, S. P; Gupta, S. S; Kariyappa, R (Springer, 1987-07)
    The intimate association between the surface magnetic fields and the Ca II K-line emission known to exist on the Sun, holds a promise for using this property to detect the presence of global magnetic fields on Sun-like ...
  • Change of level population density with time in the solar quiet chromospheric atmosphere 
    Barman, S. K; Kariyappa, R (Astronomical Society of India, 2001)
    Employing a law of weak acoustic wave, the ratio of population density N2/N1 with time for the Ca II H and K lines appropriate for the solar quiet chromosphere have been calculated. This has been done by solving the equations ...
  • Cooler and Hotter X-ray Bright Points from Hinode/XRT Observations 
    Kariyappa, R; DeLuca, E. E; Saar, S. H; Golub, L; Dame, L; Varghese, B. A (Astronomical Society of the Pacific, 2012-08)
    We use a 7-hour (17:00 UT - 24:00 UT) time sequence of soft X-ray images observed almost simultaneously in two filters (Ti_poly and Al_mesh) on April 14, 2007 with X-Ray Telescope (XRT) on-board the Hinode mission to ...
  • Coronal Rotation from XBPs Observed with Hinode/XRT 
    Kariyappa, R; DeLuca, E (Astronomical Society of the Pacific, 2012-05)
    We have selected a large number of X-ray bright points (XBPs) over synoptic soft X-ray full-disk images observed using Al-Mesh with X-Ray Telescope (XRT) onboard the Hinode spacecraft during July-December, 2008. We have ...
  • A double-pass spectrograph for solar research 
    Kariyappa, R; Jayarajan, A. P; Raheem, K. C. A; Sivaraman, K. R (Astronomical Society of India, 1993-06)
    We have described the double-pass spectrograph built at the Indian Institute of Astrophysics. Measurements of the scattered light within the spectrograph using the photoelectric scans of the NaI D-lines show that this is ...
  • Dynamical evolution of x-ray bright points with hinode/XRT 
    Kariyappa, R; Varghese, B. A; DeLuca, E. E; van Ballegooijen, A. A (Springer, 2010)
    We analyzed a 7-h long time sequence of soft X-ray images obtained on 14 April 2007 from a quiet region using the X-Ray Telescope (XRT) onboard Hinode. The aim was to observe intensity oscillations in coronal XBPs of ...
  • Dynamics of the Solar Magnetic Bright Points Derived from Their Horizontal Motions 
    Pradeep Chitta, L; van Ballegooijen, A. A; Rouppe van der Voort, L; DeLuca, E. E; Kariyappa, R (IOP Publishing, 2012-06-10)
    The subarcsecond bright points (BPs) associated with the small-scale magnetic fields in the lower solar atmosphere are advected by the evolution of the photospheric granules. We measure various quantities related to the ...
  • The Extreme Solar Activity during October–November 2003 
    Hiremath, K. M; Lovely, M. R; Kariyappa, R (Indian Academy of Sciences, 2006-09)
    The positional measurements of sunspots from the Kodaikanal Observatory and Solar Geophysical data are used to study the association between occurrence of the abnormal activities of big sunspot groups that were observed ...
  • Heating of the quiet solar chromosphere. 1: Role of the inner network bright points 
    Kariyappa, R; Sivaraman, K. R; Anandaram, M. N (Springer, 1994-05)
    We have analyzed a large number of Ca II H line profiles at the sites of the bright points in the interior of the network using a 35-min-long time sequence of spectra obtained at the Vacuum Tower Telescope (VTT) of the ...
  • Intensity oscillations and heating of the coronal X-ray bright points from Hinode/XRT 
    Kariyappa, R; Varghese, B. A (EDP Sciences, 2008-07)
    Aims. Our aim is to investigate the intensity oscillations in coronal X-ray Bright Points (XBPs). Methods. We analysed a 7 h long time sequence of the soft X-ray images obtained on April 14, 2007 with a 2 min cadence using ...
  • Intensity oscillations in chromospheric bright points and network elements 
    Kariyappa, R (Springer, 1994-09)
    From a 35-min time series of photographic spectra in the Ca II H-line obtained at the Vacuum Tower Telescope (VTT) of the Sacramento Peak Observatory under high spatial, spectral, and temporal resolution, we have derived ...
  • K-Line emission and the integrated surface magnetic field on the sun 
    Sivaraman, K. R; Kariyappa, R (Springer-Verlag Berlin Heidelberg, 1986)
    We have made plots of the Ca II K line emission vs the global surface magnetic field for the sun for the years 1975–1982 representing both solar minimum as well as solar maximum epochs. These plots show that the K-line ...
  • Long-period intensity oscillations of the quiet solar atmosphere from TRACE 1600 Å continuum observations 
    Kariyappa, R; Damé, L (Societa Astronomica Italiana, 2010)
    We have analysed a 6-hour long time sequence of ultraviolet (uv) images obtained on May 24, 2003 in 1600 Å continuum under high spatial and temporal resolutions from the Transition Region and Coronal Explorer (TRACE). ...
  • Nonlinear Force-free Field Modeling of the Solar Magnetic Carpet and Comparison with SDO/HMI and Sunrise/IMaX Observations 
    Chitta, L. P; Kariyappa, R; van Ballegooijen, A. A; DeLuca, E. E; Solanki, S. K (IOP Publishing, 2014-10-01)
    In the quiet solar photosphere, the mixed polarity fields form a magnetic carpet that continuously evolves due to dynamical interaction between the convective motions and magnetic field. This interplay is a viable source ...
  • Observational Searches for Chromospheric g-Mode Oscillationsfrom CaII H-Line Observations 
    Kariyappa, R; Dame, L; Hiremath, K. M (Indian Academy of Sciences, 2006-09)
    We have used a high spatial and temporal resolution of long time sequence of spectra in CaII H-line obtained at the Vacuum Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet region at the center of the ...
  • Observations and Modeling of the Emerging Extreme-Ultraviolet Loops in the Quiet Sun as Seen With the Solar Dynamics Observatory 
    Pradeep Chitta, L; Kariyappa, R; Van Ballegooijen, A. A; DeLuca, E. E; Hasan, S. S; Hanslmeier, A (IOP Publishing, 2013-05-01)
    We used data from the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) to study coronal loops at small scales, emerging in the quiet Sun. With HMI ...

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