Turbulent Heating and Anisotropy in the Solar Wind

Beschreibung

This book presents two important new findings. First, it demonstrates from first principles that turbulent heating offers an explanation for the non-adiabatic decay of proton temperature in solar wind. Until now, this was only proved with reduced or phenomenological models. Second, the book demonstrates that the two types of anisotropy of turbulent fluctuations that are observed in solar wind at 1AU originate not only from two distinct classes of conditions near the Sun but also from the imbalance in Alfvén wave populations. These anisotropies do not affect the overall turbulent heating if we take into account the relation observed in solar wind between anisotropy and Alfvén wave imbalance. 
In terms of the methods used to obtain these achievements, the author shows the need to find a very delicate balance between turbulent decay and expansion losses, so as to directly solve the magnetohydrodynamic equations, including the wind expansion effects. 

This book presents two important new findings. First, it demonstrates from first principles that turbulent heating offers an explanation for the non-adiabatic decay of proton temperature in solar wind. Until now, this was only proved with reduced or phenomenological models. Second, the book demonstrates that the two types of anisotropy of turbulent fluctuations that are observed in solar wind at 1AU originate not only from two distinct classes of conditions near the Sun but also from the imbalance in Alfvén wave populations. These anisotropies do not affect the overall turbulent heating if we take into account the relation observed in solar wind between anisotropy and Alfvén wave imbalance. 
In terms of the methods used to obtain these achievements, the author shows the need to find a very delicate balance between turbulent decay and expansion losses, so as to directly solve the magnetohydrodynamic equations, including the wind expansion effects. 

Nominated as an outstanding PhD thesis by the Physics Department of Paris-Sud University, Orsay, France Proves for the first time, using direct numerical simulations, that turbulent heating is one of the main contributors to solar wind heating between 0.3 and 1AU Demonstrates that the observed turbulent wave vector anisotropy at 1AU is linked to turbulent anisotropy near the Sun, and to the imbalance of Alfvén wave populations Provides results that allow us to hypothesize on the properties of solar wind turbulence near the Sun, at the end of the so-called acceleration region of the wind, and which could be verified by Parker Solar Probe and Solar Orbiter missions

Autor*in

Victor Montagud-Camps

Themen in »Turbulent Heating and Anisotropy in the Solar Wind«

Solar Wind Fluid Turbulence MHD Turbulence Numerical Simulations Plasma Physics Turbulent Heating Wave-vector Anisotropy Alfvén Wave Populations theoretical astrophysics

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