FisMat2017 - Submission - View

Abstract's title: The plasma physics of solar activity and the origins of the Heliosphere: Parker Solar Probe and Solar Orbiter.
Submitting author: Marco Velli
Affiliation: UCLA
Affiliation Address: Earth, Planetary and Space Sciences, 595 Charles E Young Dr E, Los Angeles, CA 90095
Country: United States of America
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations:
Abstract

The Sun'a magnetic activity pervades the Solar System: the Earth, Moon and other planets are immersed in a hot, rarefied, energetic flow of particles and electromagnetic fields originating from the sun, the solar wind, engulfing the entire solar system. This flow creates a bubble in the interstellar medium extending about 100 times the Earth-Sun distance, known as the Heliosphere. Inside the Heliosphere, solar magnetic fields and the nonlinear dynamical phenomena associated with their expansion from the sun dominate the space environment. The Parker Solar Probe and Solar Orbiter missions aim to understand the dynamical origins of the Heliosphere at large, the connection between the solar wind in interplanetary space to its source regions at the Sun, as well as the mechanisms leading to solar energetic particles. Solar Probe Plus will measure the plasma and magnetic fields of the outer corona and inner heliosphere in situ closer to the solar surface than any previous spacecraft. In addition, Solar Orbiter will carry out the highest latitude observations of the photospheric magnetic field, and should provide new insight into the functioning of the solar dynamo. This presentation will focus on some of the questions these exciting two missions will help elucidate: the distribution of wind speeds and magnetic fields in the inner heliosphere and their origin on the sun, the interacting fast and slow solar wind streams and the intermittent source of flow and field arising from coronal mass ejections (CMEs), and the development, acceleration and transport of energetic particles. Where and how does the sharp gradient in wind speeds develop close to the Sun? Is the wind source for fast and slow the same, and is there a steady component or is its origin always intermittent in nature? Where does the heliospheric current sheet form and how stable is it close to the Sun? What is the distribution of CME origins and is there a continuum from large CMEs to small blobs of plasma? Does the complexity of the coronal field determine the spatial distribution of energetic particle events, and what is the relative role of direct vs shock acceleration?