Magnetic reconnection A change in magnetic topology in

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Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Assume externally-driven plasma flow (inputs energy) Plasma carrying a current Magnetic fields j Jan Egedal, 2007

Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Assume externally-driven plasma flow (inputs energy) Jan Egedal, 2007

Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Assume externally-driven plasma flow (inputs energy) Jan Egedal, 2007

Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Assume externally-driven plasma flow (inputs energy) Jan Egedal, 2007

Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Magnetic configuration now has less energy Nearly all the initial magnetic energy is converted into: 1. thermal energy 2. kinetic energy on fast electrons and ions 3. kinetic energy of large scale flows Jan Egedal, 2007

Magnetic reconnection • A change in magnetic topology in the presence of a plasma

Magnetic reconnection • A change in magnetic topology in the presence of a plasma Magnetic configuration now has less energy -Magnetic energy release requires change in magnetic topology: field lines breaking and re-connecting -Reconnection is impossible in a perfectly conducting (very hot) ideal plasma, as plasma current can adjust arbitrarily (Alfvén’s theorem 1) Jan Egedal, 2007 1 see e. g. D. Griffiths, Electrodynamics