Solar Physics

, Volume 167, Issue 1–2, pp 371–380 | Cite as

The effect of gradient and curvature drifts on Forbush decreases

  • D. S. Rana
  • N. K. Sharma
  • R. S. Yadav
Article
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Abstract

The average profile of Forbush decreases, produced by eastern-, central- and western-region solar flares is obtained separately by superposed epoch analysis for the periods 1966–1969 (qA < 0) and 1971–1979 (qA > 0). It is observed that the recovery of an average Forbush decrease from the maximum depression level is faster for the situation qA > 0 than for the situation qA < 0. This is in accordance with expectations from the drift theory. It is also observed that the drift effect is more pronounced for western-flare Forbush decreases which, of course, have a smaller magnitude compared to eastern- and central-flare Forbush decreases.

The average profiles of simple and complex type Forbush decreases are also obtained separately for three periods 1965–1979, 1971–1979, and 1981–1987. It is found that the average profiles of simple and complex type Forbush decreases observed during the period 1965–1969 and 1971– 1979 are quite in agreement with drift theory. The anomalous behavior of average Forbush-decrease profiles during the period 1981–1987, especially in simple type Forbush decreases, is also explained by a drift current sheet tilt model.

Keywords

Depression Flare Current Sheet Solar Flare Small Magnitude 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • D. S. Rana
    • 1
  • N. K. Sharma
    • 2
  • R. S. Yadav
    • 3
  1. 1.S.M. College ChandausiIndia
  2. 2.College of Agriculture Engineering and TechnologyEtawahIndia
  3. 3.Department of PhysicsAligarh Muslim UniversityAligarhIndia

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