Fundamental Physics of the Slow Solar Wind - What do we Know?
Abstract
Fundamental physical properties of the slow solar wind (SSW), such as density, temperature, outflow speed, heavy ion abundances and charges states were obtained from in-situ measurements at 1AU in the past from WIND, ACE, and other spacecraft. Plasma and magnetic field measurement are available as close as 0.3 AU from Helios data, Spektr-R, and MESSENGER spacecraft. Remote sensing spectroscopic measurements are available in the corona and below from SOHO/UVCS, Hinode, and other missions. One of the major objectives of the Solar Orbiter and Solar Probe Plus missions is to study the sources of the SSW close to the Sun. The present state of understanding of the physics of the SSW is based on the combination of the existing observations, theoretical and numerical 3D MHD and multi-fluid models, that connect between the SSW sources in the corona and the heliosphere. Recently, hybrid models that combine fluid electrons and kinetic ions of the expanding solar wind were developed, and provide further insights of the local SSW plasma heating processes that related to turbulent magnetic fluctuations spectra and kinetic ion instabilities observed in the SSW plasma. These models produce the velocity distribution functions (VDFs) of the protons and heavier ions as well as the ion anisotropic temperatures. I will discuss the results of the above observations and models, and review the current status of our understanding of the fundamental physics of the SSW. I will review the open questions, and discuss how they could be addressed with near future observations and models.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSH42A..01O
- Keywords:
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- 2164 Solar wind plasma;
- INTERPLANETARY PHYSICSDE: 2169 Solar wind sources;
- INTERPLANETARY PHYSICSDE: 7509 Corona;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7524 Magnetic fields;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY