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Astrophysics Research Centre

School of Mathematics and Physics


Observing cascades of solar bullets at high resolution

  • Submitted by: Eamon Scullion, Trinity College Dublin
  • Authors: E. Scullion, O. Engvold, Y. Lin & L. Rouppe van der Voort
  • Session: Thursday morning posters.

High resolution observations from the Swedish 1-m Solar Telescope revealed bright, discrete, blob-like structures (which we refer to as solar bullets herein) in the H-alpha 656.28 nm line core, which appear to propagate laterally across the solar atmosphere as clusters in active regions (Lin et al. 2012, Paper-I). These small-scale structures appear to be field aligned and many bullets become triggered simultaneously and traverse collectively as a cluster. Here, we conduct a follow-up study on these rapidly evolving structures with co-incident observations from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). With the co-aligned data sets, we reveal (a) an evolving multi-thermal structure in the bullet cluster (b) evidence for cascade-like behavior and corresponding bi-directional motions in bullets within the cluster, which indicate that there is a common source of the initial instability leading to bullet formation © a direct relationship between coincident bullet velocities observed in H-alpha and He II 30.4 nm and an inverse relationship with respect to bullet intensity in these channels. We find evidence supporting that bullets are typically composed of a cooler, higher density core detectable in H-alpha with a less dense, hotter and fainter co-moving outer sheath detectable in 30.4 nm. They do not necessarily evolve as localised cooling or heating processes. Solar bullets unequivocally demonstrate the finely structured nature of the active region corona. We have no clear evidence for bullets being associated with locally heated, fast flowing plasma. With current observational capabilities, multiple fast sausage solitons provide the best theoretical description of the evolutionary properties of bullets.

public/hinode9/schedule/session-07p/v0080.txt · Last modified: 2015/07/30 01:39 (external edit)


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