Dissertation/Thesis Abstract

Magnetic reconnection as a chondrule heating mechanism
by Lazerson, Samuel A., Ph.D., University of Alaska Fairbanks, 2010, 102; 3436656
Abstract (Summary)

The origin of chondrules (sub-millimeter inclusions found in stony meteorites) remains today an open question despite over century of examination. The age of these proto-solar relics shows a well defined cutoff of around 4.5 billion years ago. This places them as the oldest solids in the solar system. Chemical examination indicates that they experienced heating events on the order of 5000 K/hr for periods of around 30 minutes, followed by extending periods of cooling. Additional examination indicates the presence of large magnetic fields during their formation. Most attempts to explain chondrule formation in the proto-solar nebula neglect the existence of a plasma environment, with even less mention of dust being a charge carrier (dusty plasma). Simulations of magnetic reconnection in a dusty plasma are forwarded as a mechanism for chondrule formation in the proto-solar nebula. Here large dust-neutral relative velocities are found in the reconnection region. These flows are associated with the dynamics of reconnection. The high Knudsen number of the dust particles allows for a direct calculation of frictional heating due to collisions with neutrals (allowing for the neglect of boundary layer formation around the particle). Test particle simulations produce heating equivalent to that recorded in the chondrule mineral record. It is shown that magnetic reconnection in a dusty plasma is of fundamental importance to the formation of the most primitive solids in the solar system.

Indexing (document details)
Advisor: Wiechen, Heinz
Commitee:
School: University of Alaska Fairbanks
School Location: United States -- Alaska
Source: DAI-B 72/01, Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Astrophysics, Theoretical physics, Plasma physics
Keywords: Chondrules, Dusty plasmas, Magnetic reconnection, Solar system
Publication Number: 3436656
ISBN: 9781124362441
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