The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Basic SW energy balance: Velli Solar wind Radiation Thermal Conduction

The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind “Slow” Wind: Where from? “Fast” Wind: How accelerated? Velli

The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind P. Hess (GMU) is attempting to use sun grazing comets to determine wind speed profiles in-situ. Asymptotic speed reached at ~ 12 Rsun. SPP perihelion is 9 Rs. Hess

The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Steady (“Fast”) Wind: – cooler charge states, – photospheric composition, – lower H/O ratio, – narrow H/O ratio distribution (less variable)  coronal hole source regions Unsteady (“Slow”) Wind: – hotter charge states, – coronal composition, – higher H/O ratio, – broad H/O distribution (more variable) ratio, – FIP enhanced, – Mass fractionation  suggests a multitude of source regions (e.g., loops) Zurbuchen

Charge state diagnostics: – O 6+ dominant in 1MK corona  use as a temp marker – O hotter/faster than H in fast wind  strong heating near Sun Use freeze-in temperatures of different species to constrain radial temperature profile in the corona. (Enrico Landi, UMichigan). – Freeze-in rate for C* is roughly the same (by order of magnitude)  C* freeze-in at roughly the same location. – C 6 /C 4 tracks the wind velocity. The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Zurbuchen

Linker The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Way to supply a highly variable wind from “closed” sources Larger width than the plasma sheet Asymmetric about the HCS Not clear if the (interchange) reconnections associated with the S- Web structure can energize the wind. High res simulations reveal enormous amount of structure in the magnetic field Regions of high-Q (separatrices and QSL’s) can be thought of as “seams” in the coronal magnetic field structure at which current sheets are likely to form, and where (interchange) reconnection can occur.

The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Pseudo-Streamer Streamer Belt Crooker Linker

Schwadron & McComas Scaling Law: Anti-correlation of speed and temperature. Proton flux proportional to open magnetic flux in solar wind. The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Schwadron

Reduction of open flux leads to reduced O freeze-in temperature, and therefore a reduced power in the solar wind. The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Schwadron