SHINE: Solar Wind Magnetic Field Discontinuities and the Role of Alfvenic Turbulence

University Of New Hampshire, Durham NH

Investigators

Abstract

The Principal Investigator (PI) will investigate the relationship between magnetic field discontinuities and the dissipation of turbulence in the solar wind, using a new method to accurately identify even small discontinuities in the solar wind. In a small preliminary study, this new method found numerous discontinuities with thicknesses consistent with ion kinetic scales, and these could be locations that dissipate the turbulent cascade energy. The PI will extend this initial study to all Advanced Composition Explorer (ACE) spacecraft data from March 1998 to the present, covering an entire solar activity cycle. The PI will evaluate the statistical properties of any discontinuities that are found and compare them to properties of turbulent fluctuations at the inertial dissipation range spectral break. He will also compare discontinuity frequency and other properties with local estimates of the turbulent cascade rate. This effort will help describe how small scale structures arise and contribute to heating the solar wind, as well as constrain the mechanisms responsible for the dissipation of turbulent fluctuations and the heating of ions in the solar wind near 1 AU. The PI's work will address fundamental physical processes that determine the development and evolution of the solar wind in the inner heliosphere and how small-scale processes in the solar wind couple to large-scale dynamics. This project is important for modeling the energization of the ambient solar wind through which coronal mass ejections (CMEs) must travel. Dissipation of the turbulent cascade is believed to be an important source of energizing the solar wind near Earth, and potentially from the corona to the outer heliosphere. The PI therefore expects this research to provide new approaches for magnetohydrodynamics (MHD) solar wind simulations and to enhance the accuracy of space weather forecasting. This research program will include the training and participation of both undergraduate and graduate students at University of New Hampshire.