Blob formation and acceleration in the solar wind: role of converging flows and viscosity

G. Lapenta, A. L. Restante

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The effect of viscosity and of converging flows on the formation of blobs in the slow solar wind is analysed by means of resistive MHD simulations. The regions above coronal streamers where blobs are formed (Sheeley et al., 1997) are simulated using a model previously proposed by Einaudi et al. (1999). The result of our investigation is two-fold. First, we demonstrate a new mechanism for enhanced momentum transfer between a forming blob and the fast solar wind surrounding it. The effect is caused by the longer range of the electric field caused by the tearing instability forming the blob. The electric field reaches into the fast solar wind and interacts with it, causing a viscous drag that is global in nature rather than local across fluid layers as it is the case in normal uncharged fluids (like water). Second, the presence of a magnetic cusp at the tip of a coronal helmet streamer causes a converging of the flows on the two sides of the streamer and a direct push of the forming island by the fast solar wind, resulting in a more efficient momentum exchange.

Original languageEnglish
Pages (from-to)3049-3060
Number of pages12
JournalAnnales Geophysicae
Volume26
Publication statusPublished - 2008

Keywords

  • Solar physics, astrophysics, and astronomy
  • Corona and transition region
  • Magnetic fields
  • Space plasma physics
  • Magnetic reconnection
  • Numerical simulation studies
  • CORONAL STREAMER
  • MAGNETIC RECONNECTION
  • TRIPLE STRUCTURES
  • HELMET STREAMERS
  • LARGE-ANGLE
  • BELT
  • ORIGIN
  • FIELD

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