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Browsing by Author "Raju, K. P"

Browsing by Author "Raju, K. P"

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  • High resolution interferometry of astrophysical objects 
    Raju, K. P (Astronomical Society of India, 1993)
    The thesis comprises studies on two distinctly diverse astrophysical situations; one on the outer envelope of a late-type star at its main sequence stage (solar corona), the other on the ionized cloud surrounding an ...
  • Intensity distribution and contrast of the solar EUV network 
    Raju, K. P (Springer, 2010-03)
    Intensity distributions of the EUV network and the cell interior in the solar atmosphere have been obtained in fourteen emission lines from Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) ...
  • Intensity oscillation in the corona as observed during the Total Solar Eclipse of 29 March 2006 
    Singh, J; Hasan, S. S; Gupta, G. R; Banerjee, D; Muneer, S; Raju, K. P; Bagare, S. P; Srinivasan, R (Springer, 2009-11)
    We obtained the images of the eastern part of the solar corona in the Fe xiv 530.3 nm (green) and Fe x 637.4 nm (red) coronal emission lines during the total solar eclipse of 29 March 2006 at Manavgat, Antalya, Turkey. ...
  • Lifetimes and sizes of supergranular cells 
    Raju, K. P; Srikanth, R; Singh, J (Astronomical Society of India, 1999)
    Supergranulation is the surface manifestation of large scale solar convection. Since there is a strong correspondence between supergranulation pattern and Ca K chromospheric network, lifetimes and sizes may be obtained ...
  • Line Profile Studies of Coronal Active Regions in Fe XII λ195.12 Using Hinode/EIS 
    Prabhakar, Maya; Raju, K. P (American Astronomical Society, 2022-05-20)
    Coronal active regions are studied using Hinode/EIS observations in the EUV line Fe xii λ195.12 by analyzing their line profiles from 2006 December to 2019 December. The period covers the last 2 yr of solar cycle 23 and ...
  • Narrow Band Photometry in Emission Lines during the Total Solar Eclipse of October 24, 1995 
    Singh, J; Cowsik, R; Venkatakrishnan, P; Srinivasan, R; Chinnappan, V; Raju, K. P; Srikanth, R (Indian Institute of Astrophysics, Bangalore, 1997)
    To investigate the spatial variation of tempereture and density within coronal strucures, narrow band photometry in three coronal emission lines was done during this eclipse. The emission lines 6374 (FeX), 7892 (Fe XI) and ...
  • Network and plage indices from Kodaikanal Ca-K data 
    Raju, K. P; Singh, J (IOP Publishing, 2014-02)
    The Ca II K filtergrams from Kodaikanal Solar Observatory have been used to study solar activity. The images are dominated by the chromospheric network and plages. Programs have been developed to obtain the network and ...
  • The Physical Conditions in a Polar Coronal Hole and Nearby Regions from Norikura and SOHO Observations 
    Raju, K. P; Sakurai, T; Ichimoto, K; Singh, J (The American Astronomical Society, 2000-11)
    The distribution of emission-line intensities, Doppler velocities, and line widths in a polar coronal hole and nearby regions are obtained from the spectroscopic observations carried out on 1998 November 3 at the Norikura ...
  • Possible Evidence of Long-Term Oscillations in the Solar Atmosphere 
    Raju, K. P; Singh, J; Srikanth, R; Chou, Dean-Yi; CA, TON team (Springer, 2001-03)
    We have obtained the temporal correlation function, Q(t), from time sequences of Caii K filtergrams and Dopplergrams from Antarctica, Taiwan Oscillation Network (TON) and Solar and Heliospheric Observatory (SOHO). Q(t) ...
  • Relative velocities and linewidths in a coronal hole and outside 
    Raju, K. P (Springer Netherlands, 2009-03)
    Relative Doppler velocities and spectral linewidths in a coronal hole and in the quiet Sun region outside have been obtained from Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) observations. ...
  • Search for Hydrogen-alpha Emitting Cool Pockets in Corona During the Total Solar Eclipse of October 24, 1995 
    Cowsik, R; Singh, J; Raju, K. P; Saxena, A. K; Samson, J. P. A; Naidu, B. N (Indian Institute of Astrophysics, Bangalore, 1997)
    Narrow pass band hydrogen alpha filtergrams were obtained during totality at Kalpi, to look for cool pockets of H-alpha emission in corona first observed by Bappu and Bhattacharyya during the 1970 Mexican eclipse observations. ...
  • Solar cycle variations of the EUV network characteristics from SDO/AIA 
    Varghese, Bilin Susan; Raju, K. P; Kurian, P. J; Paul, Issac (Springer Nature, 2022-01)
    It is well-known that there is a close relationship between the supergranules, magnetic field and the Extreme-UltraViolet (EUV) network of the solar atmosphere. We have obtained the network characteristics from the imaging ...
  • Spectroscopic Observation of Coronal Waves 
    Sakurai, T; Ichimoto, K; Raju, K. P; Singh, J (Springer, 2002-10)
    A time sequence over 80 min of coronal green-line spectra was obtained with a corona- graph at the Norikura Solar Observatory. Doppler velocities, line intensities, and line widths were derived through fitting a single ...
  • A Spectroscopic Study of the Solar Corona from Norikura and SOHO data 
    Raju, K. P; Sakurai, T; Ichimoto, K (International Astronomical Union, 2001)
    We report the results from a spectroscopic study of the solar corona, wherein, we examine some of the current problems in the corona, such as the plume-interplume differences in coronal holes, coronal loops in active regions ...
  • Studies of synoptic solar activity using Kodaikanal Ca K data 
    Raju, K. P (International Astronomical Union, 2017-09)
    The chromospheric network, the bright emission network seen in the chromospheric lines such as Ca ii K and Hα , outline the supergranulation cells. The Ca images are dominated by the chromospheric network and plages which ...
  • Temporal and Latitudinal Variations of the Length-Scales and Relative Intensities of the Chromospheric Network 
    Raju, K. P (Oxford University Press on behalf of the Royal Astronomical Society, 2018-08)
    The Calcium K spectroheliograms of the Sun from Kodaikanal have a data span of about 100 yr and covers over nine solar cycles. The Ca line is a strong chromospheric line dominated by chromospheric network and plages which ...
  • Temporal variations of the solar EUV network properties 
    Varghese, B.S; Raju, K. P; Kurian, P. J (Indian Academy of Sciences, 2019-07-11)
    The chromospheric network extended to the transition region as the solar EUV network disperses at the coronal level. The EUV emission lines from the transition region give information about different atmospheric heights. ...
  • Ultra-low Spatial Resolution Photometry in Near-infrared to Detect the Solar Dust Ring 
    Singh, J; Cowsik, R; Raju, K. P; Mohin, S; Ravi, K (Indian Institute of Astrophysics, Bangalore, 1997)
    There are conflicting reports about the existence of the dust ring around the Sun. An experiment to detect the solar dust ring was performed by IIA group during the total solar eclipse of Oct. 24, 1995. A near-infrared ...
  • Variation in the width of transition region network boundaries 
    Raju, K. P (Springer, 2016-12)
    The transition region network seen in solar extreme ultraviolet (EUV) lines is the extension of the chromospheric network. The network appears as an irregular web-like pattern over the solar surface outside active regions. ...
  • Velocities and linewidths in the network and cell interiors of a polar coronal hole compared with the quiet Sun 
    Raju, K. P; Bromage, B. J. I (Springer, 2014-03)
    The relative Doppler velocities and linewidths in a polar coronal hole and the nearby quiet-Sun region have been obtained from the Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) observations ...

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