Observations of multiple blobs in homologous solar coronal jets in closed loops

TL;DR

This study presents multiwavelength observations of homologous solar coronal jets, revealing their composition of bright blobs, their propagation characteristics, and the thermal properties of these blobs, enhancing understanding of jet dynamics and heating.

Contribution

It provides detailed multiwavelength analysis of homologous jets, highlighting the blob-like structure and thermal properties, which were not extensively characterized before.

Findings

Jets are composed of bright, compact blobs with sizes 4.5-9 Mm.

Blob velocities range from 140 to 380 km/s.

Blobs are multithermal with temperatures of 1.8-3.1 MK.

Abstract

Coronal bright points (CBPs) and jets are ubiquitous small-scale brightenings that are often associated with each other. In this paper, we report our multiwavelength observations of two groups of homologous jets. The first group was observed by the EUVI aboard the behind STEREO spacecraft in 171 {\AA} and 304 {\AA} on 2014 September 10, from a location where data from the SDO could not observe. The jets (J1$-$J6) recurred for six times with intervals of 5$-$15 minutes. They originated from the same primary CBP (BP1) and propagated in the northeast direction along large-scale, closed coronal loops. Two of the jets (J3 and J6) produced sympathetic CBPs (BP2 and BP3) after reaching the remote footpoints of the loops. The time delays between the peak times of BP1 and BP2 (BP3) are 240$\pm$75 s (300$\pm75$ s). The jets were not coherent. Instead, they were composed of bright and compact blobs. The sizes and apparent velocities of the blobs are 4.5$-$9 Mm and 140$-$380 km/s, respectively. The arrival times of the multiple blobs in the jets at the far-end of the loops indicate that the sympathetic CBPs are caused by jet flows rather than thermal conduction fronts. The second group was observed by the AIA aboard SDO in various wavelengths on 2010 August 3. Similar to the first group, the jets originated from a short-lived bright point (BP) at the boundary of AR 11092 and propagated along a small-scale, closed loop before flowing into the active region. Several tiny blobs with sizes of $\sim$1.7 Mm and apparent velocity of ~238 km/s were identified in the jets. We carried out the DEM inversions to investigate the temperatures of the blobs, finding that the blobs were multithermal with average temperature of 1.8$-$3.1 MK.