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Browsing by Author "Dwivedi, B. N"

Browsing by Author "Dwivedi, B. N"

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  • Density and temperature diagnostics of solar emission lines from NA VII and AL IX 
    Raju, P. K; Dwivedi, B. N; Gupta, A. K (Springer, 1994-02)
    Line intensity ratios of extreme ultraviolet (EUV) emission lines from Na VII and Al IX have been considered for electron density and temperature determinations within the chromosphere-corona transition region and the ...
  • Density and Temperature Diagnostics of Solar Emission Lines from NeV/MgV and SiVII/MgVII Ions 
    Mohan, A; Dwivedi, B. N; Raju, P. K (Indian Academy of Sciences, 1999-06)
    We present NeV/ MgV and SiVII/MgVII theoretical line intensity ratios as a function of electron density Ne and temperature Te. These are shown in the form of ratio-ratio diagrams, which should in principle allow both Ne ...
  • Density dependence of solar emission lines of boron-like ions 
    Dwivedi, B. N; Raju, P. K (Kluwer Academic Publishers, 1980-11)
    Steady state level densities of 20 levels of the boron-like ions Mg VII and Si X have been computed as a function of electron density and temperature. Collisional and spontaneous radiative processes have been accounted ...
  • Density dependence of solar emission lines of carbon-like ions 
    Raju, P. K; Dwivedi, B. N (Indian Academy of Sciences, 1979-09)
    Steady state level population of 15 levels of carbon-like ions: NeV, MgVII, SiIX, and SXI have been computed as a function of electron density and temperature taking into account collisional processes and spontaneous ...
  • Density dependence of solar emission lines of oxygen-like ions 
    Raju, P. K; Dwivedi, B. N (D.Reideal Publishing Co.,, 1978-12)
    Assuming steady state conditions, the occupation of 9 levels of oxygen-like ions: Ne iii, Mg v, Si vii, S ix, and Ar xi have been computed as a function of electron density and temperature. The following physical processes ...
  • Density diagnostics of solar emission lines from nitrogen-like ions 
    Dwivedi, B. N; Raju, P. K (Elsevier, 1988)
    Steady state level population of 13 levels of nitrogen-like ions; Ne IV, Mg VI, Si VIII, and S X have been computed as a function of electron density and temperature. We have accounted for collisional and spontaneous ...
  • Diagnostic study of prominence-corona interface 
    Raju, P. K; Dwivedi, B. N (Havard Observatory, 1989)
  • Diagnostic study of prominence-corona interface 
    Raju, P. K; Dwivedi, B. N (Springer, 1990)
  • Diagnostics of solar plasma using emission lines 
    Dwivedi, B. N (Indian Institute of Astrophysics, Bangalore, 1988)
    The spectroscopic techniques in the X- and EUV region to determine electron density and temperature of solar plasma have been presented. The line intensity ratios as a diagnostic probe of solar plasma from berrylium, boron, ...
  • Effect of steady flow and Newton's cooling on the propagation and damping of small-amplitude prominence plasma oscillations 
    Singh, K. A. P; Dwivedi, B. N (Cambridge University Press, 2009-08)
    In study the propagation and damping of small-amplitude prominence oscillations invoking steady flow and radiative losses due to Newton's cooling with constant relaxation time. We find that the strength of steady flow has ...
  • Emission lines from nitrogen-like ions and their diagnostic use 
    Raju, P. K; Dwivedi, B. N (Kluwer Academic Publishers, 1990-11)
    Line emissions from nitrogen-like ions NeIV, MgVI, and AlVII have been studied as a diagnostic probe for the emitting regions of astrophysical plasma. Line intensities from these ions have been calculated and compared, in ...
  • EUV diagnostics for boron-like ions from spectra obtained by SUMER/SOHO 
    Mohan, A; Dwivedi, B. N (Astronomical Society of India, 2002-09)
  • Evolution of Kelvin–Helmholtz Instability in the Fan-spine Topology 
    Mishra, S. K; Singh, Balveer; Srivastava, A. K; Kayshap, Pradeep; Dwivedi, B. N (IOP Publishing, 2021-12-10)
    We use multiwavelength imaging observations from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory to study the evolution of the Kelvin–Helmholtz (K–H) instability in a fan-spine magnetic field ...
  • Fe XIV green/Fe XIII infrared line ratio diagnostics 
    Srivastava, A. K; Singh, J; Dwivedi, B. N; Muneer, S; Sakurai, T; Ichimoto, K (Astronomical Society of India, 2007-12)
    We consider the first 27-level atomic model of Fe XIII (5.9 K < log Te < 6.4 K) to estimate its ground level populations, taking account of electron as well as proton collisional excitations and de-excitations, radiative ...
  • Line emission from the quiet sun and the coronal hole regions 
    Dwivedi, B. N; Raju, P. K (Astronomical Society of India, 1985-12)
    Using Kopp & Orrall (1976) model for the electron density and temperature for the quiet sun and the coronal hole regions, we have computed emission line intensities from Mg VIII, Si X (boron-like); Mg VII, Si IX (Carbon-like) ...
  • On the EUV Line Diagnostics From N III Solar Ion 
    Gupta, A. K; Mohan, A; Dwivedi, B. N (Astronomical Society of India, 1997)
    We present new calculations for N III ion for diagnostics of solar plasma. The atomic model comprising the first 15 energy levels is considered for evaluating the line emissivities as a function of electron density and ...
  • On the line ratio diagnostics for NeV, MgV, SiVII and Mg VII solar ions 
    Dwivedi, B. N; Mohan, Anita; Raju, P. K (Elsevier, 1997)
    We present NeV/MgV and MgVII/SiVII theoretical line intensity ratios as a function of electron density and temperature for physical conditions within the solar chromosphere-corona transition region. The electron pressure ...
  • Our Present Understanding of Solar Flares 
    Dwivedi, B. N (Indian Institute of Astrophysics, Bangalore, 1986)
    A general discussion of solar flares with emphasis on two-ribbon flares is given. The basic differences between compact (simple-loop) and two-ribbon flares have also been pointed. Skylab observations have been presented ...
  • Plasma diagnostics for SUMER on board the SOHO mission 
    Dwivedi, B. N (Astronomical Society of India, 1996)
    We highlight a rich source of high-resolution EUV observations that the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, on board the SOHO mission, is capable of making in the broad spectral range ...
  • Probing the Sun's hot atmosphere: Views from Yohkoh, SOHO and TRACE 
    Dwivedi, B. N (Astronomical Society of India, 2002-09)
    This article reviews some recent progress in our understanding of the Sun's hot atmosphere. using data from spacecraft (Yohkoh, SOHO and TRACE) and from ground-based eclipse experiments.

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