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

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

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

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

5. 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

6. 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 theorem1) 1see e.g. D. Griffiths, Electrodynamics Jan Egedal, 2007