Chromospheric jets around the edges of sunspots

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.

Fast Magnetic Reconnection in the Solar Chromosphere Mediated by the Plasmoid Instability

“…Their velocity is usually found in the range of 10-150 km s −1 . The average speed of chromospheric jets around the edges of sunspots is around 30 km s −1 (Morton 2012). Fig.…”

Magnetic Reconnection in Strongly Magnetized Regions of the Low Solar Chromosphere

“…In the low solar atmosphere, the plasma density varies sharply with height and the ionization degree of hydrogen also varies from 10 −4 in the photosphere to 1 at the top of the chromosphere (Vernazza et al 1981;Fontenla et al 1993). Dynamical events, such as chromospheric jets (e.g., Liu et al 2009;Morton 2012;Bharti et al 2013;Tian et al 2014), Ellerman Bombs (e.g., Fang et al 2006;Hong et al 2014;Nelson et al 2015) and type II white light flares (e.g., Ding et al 1994Ding et al , 1999, are all related to magnetic reconnection in the partially ionized low atmosphere. Improvements in the angular resolution of solar telescopes have allowed many small scale magnetic reconnection events in the low solar atmosphere to be observed (e.g., Yang et al 2015;Xue et al 2016;Zhao et al 2017).…”

Heating Mechanisms in the Low Solar Atmosphere Through Magnetic Reconnection in Current Sheets

“…As the resolution of solar telescopes continue to be improved, many tiny activities relating with magnetic reconnection in the lower solar atmosphere have been observed, e.g., chrompshere jets (Liu et al 2009;Morton 2012;Bharti et al 2013), Ellerman Bombs (EBs) (Fang et al 2006;Pariat et al 2007;Hong et al 2014;Nelson et al 2015) and type II white light flares (Ding et al 1994(Ding et al , 1999. Recently, the clear magnetic reconnection events in the low solar atmosphere have been observed by the high resolution Chinese New Vacuum Solar Telescope (NVST), the current sheet structures, inflow and outflow have been clearly identified (Yang et al 2015).…”

“…Morton 2012;Bharti et al 2013;Tian et al 2014). Compared with corona jets, they are tiny and some with a length even less than 1 and width less than 0.3 (Bharti et al 2013;Tian et al 2014).…”

“…The life time of these micro jets could be only around one minute (Bharti et al 2013;Tian et al 2014). The rise speed of these jets is usually in a range 10 − 100 km s −1 Morton (2012), and the temperature of the chromosphere material can be heated to higher than 10 5 K (Morton 2012;Tian et al 2014). However, magnetic reconnection takes place at which height of the solar chromosphere and where the high temperature plasmas are generated in the chromosphere jets are still not clear.…”