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

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Presentation on theme: "The Role of Magnetic Geometry and Reconnection in the Origin of the Solar Wind Basic SW energy balance: Velli Solar wind Radiation Thermal Conduction."— Presentation transcript:

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

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

3 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

4 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

5 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

6 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.

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

8 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

9 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


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