Chromospheric jets around the edges of sunspots^⋆

Solar Physics and Space Plasma Research Centre (SP²RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
e-mail: r.j.morton@sheffield.ac.uk

Received: 29 February 2012
Accepted: 3 May 2012

Abstract

Aims. Evidence is beginning to be put forward that demonstrates the role of the chromosphere in supplying energy and mass to the corona. We aim to assess the role of chromospheric jets in active region dynamics.

Methods. Using a combination of the Hinode/SOT Ca II H and TRACE 1550 Å and 1600 Å filters we examine chromospheric jets situated at the edge of a sunspot.

Results. Analysis reveals a near continuous series of jets, that raise chromospheric material into the low corona above a sunspot. The jets have average rise speeds of 30 km s^-1 and a range of 10−100 km s^-1. Enhanced emission observed at the jets leading edge suggests the formation of a shock front. Increased emission in TRACE bandpasses above the sunspot and the disappearance of the jets from the Ca II filter suggests that some of the chromospheric jet material is at least heated to  ~0.1 MK. The evidence suggests that the jets could be a source of steady, low-level heating for active region features.