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Solar Physics

, Volume 104, Issue 2, pp 431–445 | Cite as

In-situ observations of the latitudinal gradients of the solar wind parameters during 1976 and 1977

  • R. Bruno
  • U. Villante
  • B. Bavassano
  • R. Schwenn
  • F. Mariani
Article

Abstract

Interplanetary observations from Helios 1, Helios 2, and IMP-8 spacecraft during 1976 and 1977, namely the early portion of solar cycle 21, have been used to investigate the latitudinal gradients of the solar wind parameters with respect to the angular displacement from the current sheet inferred from synoptic HAO white-light maps of the solar corona at 1.75 solar radii. A latitudinal belt of ±25 deg around the current sheet has been investigated. Large gradients for solar wind flow speed, proton density and temperature have been found. Smoother gradients were also found for particle flux, kinetic, gravitational and thermal energy density flux. All these gradients revealed to become smoother going towards the solar cycle's maximum. Neither latitudinal nor temporal variations were identified for magnetic and thermal energy density. A remarkable result of this study is that the momentum flux density and the total energy flux density which other authors found to be independent of any longitudinal stream structure were also found to be independent of any latitudinal structure. Moreover, these two parameters did not show any temporal variation during the period of interest.

Keywords

Solar Wind Solar Cycle Current Sheet Helios Latitudinal Gradient 
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

© D. Reidel Publishing Company 1986

Authors and Affiliations

  • R. Bruno
    • 1
  • U. Villante
    • 2
  • B. Bavassano
    • 3
  • R. Schwenn
    • 4
  • F. Mariani
    • 5
  1. 1.Istituto di Fisica dello Spazio Interplanetario, CNRFrascatiItaly
  2. 2.Dipartimento di FisicaUniversita'L'AquilaItaly
  3. 3.Istituto di Fisica dello Spazio Interplanetario, CNRFrascatiItaly
  4. 4.Max-Planck-Institut für AeronomieKatlenburg-Lindau 3F.R.G.
  5. 5.Dipartimento di FisicaII Universita'RomeItaly

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