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Browsing Publications of Astronomical Society of India by Subject "Solar activity"

Browsing Publications of Astronomical Society of India by Subject "Solar activity"

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  • `1.3-Year' and `153-day' Periodicities in the Sun's Surface Rotation 
    Javaraiah, J (Astronomical Society of India, 2003)
    Using the daily Mt. Wilson velocity data during 1986-1994, we found 1.3 ± 0.1 yr periodicity - is dominant in the Sun's surface `mean' rotation rate (A ) during 1986-1994 (solar cycle 22). A 153 ± 5 - day periodicity found ...
  • Comparative study of diurnal anisotropy in CR intensity on quiet days and all days 
    Santosh Kumar; Gulati, U; Khare, D. K; Richharia, M. K (Astronomical Society of India, 1993)
    A comparative study of the diurnal variation of cosmic ray (CR) intensity has been performed on geomagnetically quiet days (QD) and all days (AD) using neutron monitor data for the year 1987. It is observed that even though ...
  • Mechanism of the solar cycle : recent results and new ideas 
    Gokhale, M. H (Astronomical Society of India, 1998)
    A recheck of our computations and arguments confirm our recent inferences (Gokhale, 1996) about: (a) existence of variations of ~ 1 % in the Sun's spin angular momentum on time scales of planetary orbits, (b) coupling of ...
  • On the disappearance of H-alpha filaments and soft X-ray enhancements as seen from Yohkoh SXT 
    Singh, J; Sakurai, T; Ichimoto, K (Astronomical Society of India, 2001)
    We have studied H-alpha images of the sun taken at Kodaikanal and Mitaka observatories and soft X-ray images obtained by SXT onboard Yohkoh for the years 1993 and 94. From events of disappearing quiescent H-alpha filaments ...
  • A relation between frequency shift and the changes in activity indices 
    Jain, K; Tripathy, S. C; Kumar, B; Bhatnagar, A (Astronomical Society of India, 2000)
    We present a linear relation between the shift in p-mode frequencies and variation in two solar activity indices, namely the sunspot number and 10.7 cm radio flux. From this relation, an empirical model is constructed to ...
  • Short-term periodicities of solar differential rotation 
    Javaraiah, J (Astronomical Society of India, 1998)
  • Solar granulation and speckle interferometry 
    Gupta, K. G; Pande, M. C (Astronomical Society of India, 1992)
    The status of various applications of speckle interferometry and imaging to the study of solar granulations as well as solar activity is reviewed. The physical aspects of solar granulations are examined, with emphasis on ...
  • The study of cosmic ray intensity distribution near earth 
    Shrivastava, P. K; Shukla, R. P (Astronomical Society of India, 1993)
    The cosmic ray density distribution near earth is generally investigated by using the yearly excursion in the heliographic latitudinal position of earth. The study has been done for 1978 to 1990 to determine the density ...
  • Study of solar wind using single-station interplanetary scintillation 
    Manoharan, P. K (Astronomical Society of India, 1993)
    This thesis is based on the study of interplanetary scintillation (IPS) measurements using compact radio sources. In this study, I have shown for the first time that the solar-wind velocities may be estimated reliably and ...
  • Surge activities on November 26-28, 1990 
    Uddin, W; Verma, V. K (Astronomical Society of India, 2000)
    We report here a study of 8 solar surges observed in H? emission on the west solar limb (active region NOAA 6368) on 26, 27 and 28 November 1990. Three surges were observed on 26 November of durations 35, 86 and 40 min at ...

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