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Browsing by Author "Gangadhara, R. T"

Browsing by Author "Gangadhara, R. T"

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  • Mean-field dynamo in partially ionized plasmas – I 
    Krishan, V; Gangadhara, R. T (Blackwell Publishing, 2008-04)
    There are several astrophysical situations where one needs to study the dynamics of magnetic flux in partially ionized turbulent plasmas. In a partially ionized plasma, the magnetic induction is subjected to the ambipolar ...
  • Millisecond pulsar emission altitude from relativistic phase shift: PSR J0437-4715 
    Gangadhara, R. T; Thomas, R. M. C (Springer Netherlands, 2008)
    We have analyzed the profile of the millisecond pulsar PSR J0437-4715 at 1440 MHz by fitting the Gaussians to pulse components, and identified its 11 emission components. We propose that they form a emission beam with 5 ...
  • A Model for Simulating Realistic Profiles of Pulsars 
    Thomas, R. M. C; Gupta, Y; Gangadhara, R. T (American Institute of Physics, 2011-08)
    We devise an accurate method to compute the emission profile corresponding to a given set of pulsar emission parameters, for eg. inclination angle alpha, impact angle beta, frequency of emission omega, Lorentz factor gamma, ...
  • Modeling of polarization of radio pulsars 
    Gangadhara, R. T (Astronomical Society of the Pacific, 2009-09)
    We have generalized the coherent curvature radiation model to include the detailed geometry of the emission region in pulsar magnetosphere, and deduced the polarization state in terms the Stokes parameters. By considering ...
  • Modelling sunspot equilibrium through a solution of the time dependent MHD equations 
    Gangadhara, R. T; Hasan, S. S (Astronomical Society of India, 1996)
    We numerically simulate the dynamical relaxation to equilibrium of a sunspot. Treating the sunspot as a thick axisymmetric flux tube in cylindrical geometry, we solve the time dependent MHD equation to examine the evolution ...
  • The modulation of radiation in an electron-positron plasma 
    Gangadhara, R. T; Krishan, V; Shukla, P. K (Royal Astronomical Society, 1993-05-01)
    The modulational instability of a large-amplitude, linearly polarized electromagnetic wave propagating in an electron-positron plasma is considered, including the combined effect of relativistic mass variation of the plasma ...
  • Neutron star physics in the square kilometre array era: an Indian perspective 
    Konar, S; Bagchi, Manjari; Bandyopadhyay, Debades; Banik, Sarmistha; Bhattacharya, D; Bhattacharyya, S; Gangadhara, R. T; Gopakumar, A; Gupta, Y; Joshi, B. C; Maan, Yogesh; Maitra, Chandreyee; Mukherjee, D; Pai, Archana; Paul, B; Ray, A; Sutaria, F. K (Indian Academy of Sciences, 2016-12)
    It is an exceptionally opportune time for astrophysics when a number of next-generation mega-instruments are poised to observe the Universe across the entire electromagnetic spectrum with unprecedented data quality. The ...
  • Nonlinear Propagation of Intense Electromagnetic Waves in Quasar and Pulsar Plasmas 
    Gangadhara, R. T (Astronomical Society of India, 1997)
    We present the results of analytical as well as numerical investigations of radiation-plasma interaction instabilities in astrophysical plasmas. We consider the stimulated Raman and Compton scattering in the continuum ...
  • Nonlinear Propagation of Intense Electromagnetic Waves in Quasar and Pulsar Plasmas 
    Gangadhara, R. T (Indian Institute of Astrophysics, Bangalore, 1993-04)
  • On the method of estimating emission altitude from relativistic phase shift in pulsars 
    Gangadhara, R. T (The University of Chicago Press, 2005-08-01)
    The radiation by relativistic plasma particles is beamed in the direction of field-line tangents in the corotating frame, but in an inertial frame it is aberrated toward the direction of rotation. We have revised the ...
  • Parametric decay instability in 3C 273 
    Gangadhara, R. T; Krishan, V (Cambridge University Press, 1991)
    The parametric decay instability (PDI) causes anomalous absorption of strong electromagnetic (e.m) radiation under specific conditions of energy and momentum conservation. It is shown that in the source 3C 273, the conditions ...
  • Polarization Changes of Radiation through Stimulated Raman Scattering 
    Gangadhara, R. T; Krishan, V (The American Astronomical Society, 1993-10)
    We study change in the polarization of electromagnetic waves due to the stimulated Raman scattering in a plasma. In this process an electromagnetic wave undergoes coherent scattering off an electron plasma wave. It is found ...
  • Polarization of coherent curvature radiation in pulsars 
    Thomas, R. M. C; Gangadhara, R. T (Springer Netherlands, 2008)
    We consider the coherent curvature radiation by relativistic plasma in pulsar magnetosphere. The radiation emitted by relativistic particle bunches is beamed in the direction of field line tangents. For the first time, we ...
  • Propagation effects on polarization of pulsar radio emission 
    Gangadhara, R. T; Lesch, H; Krishan, V (The Royal Astronomical Society, 1999-08)
    We consider the role of a propagation effect such as stimulated Raman scattering on the polarization of radio pulses. When an intense electromagnetic wave with frequency close to the plasma frequency interacts with the ...
  • Pulsar Radio Emission Altitude from Curvature Radiation 
    Gangadhara, R. T (The University of Chicago Press, 2004-07-01)
    We assume that relativistic sources moving along dipolar magnetic field lines emit curvature radiation. The beamed emission occurs in the direction of tangents to the field lines, and to receive it, the sight line must ...
  • Pulsar radio emission geometry 
    Gangadhara, R. T (Springer Netherlands, 2008)
    Pulsar radio emission is belived to come from relativistic plasma accelerated along the dipolar magnetic field lines in pulsar magnetosphere. The beamed emission by relativistic sources occur in the direction of tangents ...
  • Radio Emission by Particles Accelerated in Pulsar Magnetosphere 
    Thomas, R. M. C; Gangadhara, R. T (Astronomical Society of India, 2003)
    We present a relativistic model of pulsar radio emission by plasma accelerated along the rotating magnetic field lines projected on to a 2D plane perpendicular to the rotation axis. We have derived the expression for the ...
  • Radio emission by particles due to pulsar spin 
    Thomas, R. M. C; Gangadhara, R. T (EDP Sciences, 2005-07)
    We present a relativistic model for the motion of charged particles in rotating magnetic field lines projected onto a plane perpendicular to the rotation axis. By making an approximation that the projected field lines are ...
  • Radio wave heating of astrophysical plasmas 
    Gangadhara, R. T; Krishan, V (Indian Academy of Sciences, 1990-12)
    The coherent plasma process, parametric decay instability (PDI), has been applied to a homogeneous and unmagnetized plasma. These instabilities cause anomalous absorption of strong electromagnetic radiation under specific ...
  • Rapid polarization variability in intense sources 
    Gangadhara, R. T; Krishan, V (The American Astronomical Society, 1995-02)
    We have recently reported the polarization changes of the intense electromagnetic radiation, in active galactic nuclei and pulsars, due to stimulated Raman scattering. In this paper, we show that the incident and the ...

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