Observation of thin current sheets during magnetotail reconnection with a presence of a guide field

Thin current sheets are known to play a central role in magnetotail physics. Formation of a thin current layer is a necessary condition for magnetic reconnection in a collisionless plasma. Using the four-point measurements by Cluster separated on a spatial scale of less than an ion inertia length, we examined detailed profiles of ion-scale current sheets during reconnection events. In particular, we focus on reconnection events with a large guide field. Strong guide field cases in magnetotail reconnection have been rarely reported so far, since on average a guide field is not expected to play a central role in magnetotail. Yet, some local (temporal) fluctuations and tilt of the current sheet may create an "effective" guide field and associated signatures are detected in the particle distribution and the structure of the current sheet. The obtained structures are compared with the results from simulations.