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Observations of magnetic reconnection and particle acceleration locations in solar coronal jets

Yixian Zhang (University of Minnesota) zhan6327@umn.edu

Sophie Musset (ESA/ESTEC)

Lindsay Glesener (University of Minnesota)

Navdeep Panesar (LMSAL/BAERI)

Gregory Fleishman (New Jersey Institute of Technology)

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Outline

  • How are coronal jets generated?
  • Observations of two coronal jets on November 13, 2014
  • Differential emission measure (DEM) analysis
  • Imaging spectroscopy: accelerated electron populations
  • Discussion: particle acceleration locations

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jets can be driven by minifilament eruption

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  • Jets are generally formed by magnetic reconnection between open and closed magnetic field lines.

Sterling et al. (2015, 2016)

Flare model

Shibata et al. (1995)

Minifilament

Hot plasma and HXR emissions are expected to be near the jet base.

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Two recurrent Coronal jets on Nov 13, 2014

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Minifilament

17:16:08, Jet base

AIA observations (Jet1)

RHESSI observed 4 HXR sources, including two near the top of the jet.

Jet 1

Jet 2

Jet 2

Jet 2

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Differential emission measure (DEM) Analysis

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Fe line emission

To predict both the HXR continuum and the line feature well, a cross-calibration factor of ~3.5 between AIA and RHESSI was required.

AIA-alone DEM vs Joint DEM

HXR spectra

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Imaging spectroscopy: evidence of accelerated electrons

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Mild particle energization

 

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Particle acceleration locations: near the HXR sources

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+: 4 HXR sources with/without the cross-calibration factor applied

Collisional stopping distance for non-thermal electrons

Stopping distance along the jet body: 20-30 arcsec

Separation between the base and top HXR sources: ~80 arcsec

The HXR sources at the top of each jet was produced by electrons that were accelerated very close to this source.

=> more than one reconnection/particle acceleration site in a single jet event!

 

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Summary

  • Incorporating RHESSI data in the DEM analysis helps constrain the amount of hot plasma.
  • Four RHESSI HXR sources were observed including two in the corona. Mildly energetic electrons were found at all these locations.
  • The non-thermal electrons contain a large amount of total energy.
  • The particle acceleration/reconnection sites are close to the HXR source location, which means that there is more than one particle acceleration site in each jet event.

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Manuscript submitted to ApJ. (Would also be available on arXiv shortly.)

Contact: zhan6327@umn.edu

Acknowledgement: This work is supported by NASA Heliophysics Guest Investigator grant 80NSSC20K0718 and NASA FINESST program 80NSSC21K1387.

SPHERE workshop, July 12, 2022