title: Magnetic reconnection triggering magnetohydrodynamic instabilities during a sawtooth crash in a Tokamak plasma.
abstract: Thomson scattering measurements with subcentimeter spatial resolution have been made during a sawtooth crash in a Mega Ampere Spherical Tokamak fusion plasma. The unparalleled resolution of the temperature profile has shed new light on the mechanisms that underlie the sawtooth. As magnetic reconnection occurs, the temperature gradient at the island boundary increases. The increased local temperature gradient is sufficient to make the helical core unstable to ideal magnetohydrodynamic instabilities, thought to be responsible for the rapidity of the collapse.
authors.affiliation: EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom.
authors.forename: I T
authors.initials: IT
authors.lastname: Chapman
authors.forename: R
authors.initials: R
authors.lastname: Scannell
authors.forename: W A
authors.initials: WA
authors.lastname: Cooper
authors.forename: J P
authors.initials: JP
authors.lastname: Graves
authors.forename: R J
authors.initials: RJ
authors.lastname: Hastie
authors.forename: G
authors.initials: G
authors.lastname: Naylor
authors.forename: A
authors.initials: A
authors.lastname: Zocco