Local measurement of nonclassical ion heating during magnetic reconnection

Local ion temperature and flows are measured directly in the well-character ized reconnection layer of a laboratory plasma. The measurements indicate s trongly that ions are heated due to reconnection and that more than half of the reconnected field energy is converted to ion thermal energy. Neither c lassical viscous damping of the observed sub-Alfvenic ion flows nor classic al energy exchange with electrons is sufficient to account for the ion heat ing, suggesting the importance of nonclassical dissipation mechanisms in th e reconnection layer.