IIAP Publications: Recent submissions

  • Rotation and H-alpha emission activity in F8-G3 dwarfs 
    Mekkaden, M. V (Kluwer Academic Publishers, 1985-12)
    The dependence of H-alpha emission strength on rotational period and spectral type in late-type stars is studied using published data. The emission strength shows strong correlation with rotation irrespective of age and ...
  • Evolution of coronal helicity in a twisted emerging active region 
    Ravindra, B; Longcope, D. W (Springer, 2010)
    Active-region magnetic fields are believed to be generated near the shear layer of the convection zone by dynamo processes. These magnetic fields are concentrated into fluxtubes, which rise, due to buoyancy, through the ...
  • Long-term variations in meridional flows 
    Javaraiah, J (Springer, 2010)
    Using sunspot group data from Greenwich and from the Solar Optical Observation Network during 1879–2008, we find that the mean meridional motion of the observed spot groups varies considerably on a time scale of about 10–20 ...
  • Low-frequency radio observations of coronal magnetic fields 
    Ramesh, R; Sonnett, S. M; Kathiravan, C (Springer, 2010)
    We report observations of circularly polarized noise storm emission from the solar corona at 77 and 109MHz during the period 11–18 August 2006 (Carrington Rotation 2046) with the recently commissioned East-West one-dimensional ...
  • Waves in polar coronal holes 
    Banerjee, D (Springer, 2010)
    The fast solar wind originates from polar coronal holes. Recent observations from SoHO suggest that the solar wind is flowing from funnel-shaped magnetic fields anchored in the lanes of the magnetic network at the solar ...
  • Stability of cool flux tubes in the solar chromosphere Linear analysis 
    Hasan, S. S; Kneer, F (EDP Sciences, 1986-04)
    The linear stability of cool flux tubes in the solar chromosphere which are initially in radiative equilibrium is examined. Owing to the presence of carbon monoxide, there exists a narrow region near the temperature minimum ...
  • Equilibrium structure of solar magnetic flux tubes: Energy transport with multistream radiative transfer 
    Hasan, S. S; Kalkofen, W (The American Astronomical Society, 1994-11)
    We examine the equilibrium structure of vertical intense magnetic flux tubes on the Sun. Assuming cylindrical geometry, we solve the magnetohydrostatic equations in the thin flux-tube approximation, allowing for energy ...
  • Mode classification and wave propagation in a magnetically structured medium 
    Hasan, S. S; Sobouti, Y (Blackwell, 1987-09)
    The authors examine the structure of motions that can occur in a vertical magnetic flux tube with a rectangular cross-section. A polytropic stratification is assumed in the vertical direction. The authors use a gauged ...
  • NLST: India's National Large Solar Telescope 
    Hasan, S. S; Soltau, D; Kärcher, H; Süß, M; Berkefeld, T (Wiley-Blackwell, 2010-06)
    This article introduces the new Indian 2 m telescope which has been designed by MT Mechatronics in a detailed conceptual design study for the Indian Institute of Astrophysics, Bangalore. We describe the background of the ...
  • Republication of: radial movement in sunspots 
    Hasan, S. S (Springer, 2010)
    Displacements of the lines of hydrogen and calcium in the neighbourhood of sunspots, indicating violent motions in the line of sight, is a common characteristic of spot disturbances. Such phenomena are frequently observed ...
  • Spectropolarimetry with the NLST 
    Sankarasubramanian, K; Hasan, S. S; Rangarajan, K. E (Springer, 2010)
    India’s National Large Solar Telescope (NLST) will provide opportunities to observe the Sun with high spatial, spectral, and polarimetric resolution. The large aperture also enables high-cadence spectropolarimetry with ...
  • Evershed flow velocities during 100 years 
    Hiremath, K. M (Springer, 2010)
    An extensive literature survey indicates that the peak velocities of the Evershed flows in sunspots at the photospheric level are independent of the strength of the solar activity cycle. This result is discussed in the ...
  • Evidence for return meridional flows in the convection zone 
    Sivaraman, K. R; Sivaraman, H; Gupta, S. S; Howard, R. F (Springer, 2010)
    We report velocities of meridional motions derived from the latitude drifts of spot groups measured on photographic images of the Sun in the Kodaikanal observatory archives. They serve to measure different meridional flows ...
  • The thermal structure of sunspots 
    Hiremath, K. M; Akshatha, B. B (Springer, 2010)
    We use SOHO/MDI continuum images to measure the average thermal structure of bipolar spots during their initial appearance. Although the average thermal structure of penumbrae is independent of sunspot size and life span, ...
  • Study of Compton broadening due to electron-photo scattering 
    Srinivasa Rao, M (Astronomical Observatory, Serbia, 2010-06)
    SUMMARY: We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an ...
  • Time-resolved spectral observations of spicule velocities at several heights 
    Hasan, S. S; Keil, S. L (American Astronomical Society, 1984-08)
    The vacuum telescope of the National Solar Observatory, Sacramento Peak was used to obtain H-alpha spectral observations of spicules. A set of spectra corresponding to five slit positions above the solar limb were recorded ...
  • Interior and exterior clues of solar activity 
    Turck-Chièze, S; Brun, A. S; Duez, V; García, R. A; Mathis, S; Piau, L; Salabert, D; Pallé, P. L; Jiménez-Reyes, S. J; Mathur, S; Simoniello, R; Robillot, J. M (Springer, 2010)
    Two research paths are described to obtain better understanding of the origin of global solar activity. First, observations with a multichannel resonant spectrometer may reveal the dynamics of the solar core, the tachocline, ...
  • Viscous damping of Alfven surface waves with steady flows 
    Rathinavelu, G. D; Sivaraman, M; Satya Narayanan, A (Springer, 2010)
    The dispersion relation of Alfvén Surface Waves propagating along the moving viscous plasma–vacuum interface has been derived and solved numerically. The plasma layer is below while the upper layer is assumed to be vacuum. ...
  • Revisit of the classic Wilson effect 
    Bagare, S. P (Springer, 2010)
    We have examined theWilson effect in 580 epochs of sunspots observed at the Kodaikanal Observatory. Only unipolar spots that are well isolated from opposite polarity spots or pores (49%) exhibit the classic Wilson effect. ...
  • Are polar faculae generated by a local dynamo? 
    Sivaraman, K. R; Antia, H. M; Chitre, S. M (Springer, 2010)
    Polar faculae (PF) are bright, small-scale structures measuring a few seconds of arc, populating the polar zones at latitudes >50°. They possess magnetic fields ranging from 150 to 1,700 Gauss and largely constitute the ...

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