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Stochastic Seismic Emission from Acoustic Glories in New Active Regions of cycle 24

Stochastic Seismic Emission from Acoustic Glories in New Active Regions of cycle 24. Alina Donea Centre for Stellar and Planetary Astrophysics Monash University. Holographic images of seismic emissions in AR10486. acoustic glory = enhanced seismic emission 5mHz, halo (Braun, Lindsey 1992).

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Stochastic Seismic Emission from Acoustic Glories in New Active Regions of cycle 24

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  1. Stochastic Seismic Emission from Acoustic Glories in New Active Regions of cycle 24 Alina Donea Centre for Stellar and Planetary Astrophysics Monash University GONG2010/SOHO24

  2. Holographic images of seismic emissions in AR10486 acoustic glory = enhanced seismic emission 5mHz, halo (Braun, Lindsey 1992) Local helioseismic technique: helioseismic holography (Lindsey, Braun 1997) GONG2010/SOHO24

  3. Holographic images of seismic emission in AR • 2.5-4.5 mHz - seismic deficit up to 30 Mm outside of surface mgn regions • >4.5 mHz - seismic deficit in AR only + - acoustic glory (halo of sharply enhanced seismic emission, small, discrete emitters; thin bead strings) - only around large-multipolar AR (15% excess of mean QS) GONG2010/SOHO24

  4. Emitters cluster in strings 1 emitter size=3Mm, acoustic diffraction limit@5mHz 1 emitter : Seismic EG power =1.5%QS Non-magnetic regions or border weak magnetic region (Donea, Lindsey,Braun 2000) GONG2010/SOHO24

  5. Temporal character of seismic emission from acoustic glories / Quiet Sun (QS) GONG2010/SOHO24

  6. Power distribution of 5mHz EG POW emission from acoustic glories / Quiet Sun (QS) HO2=1.51 Hquiet2 Control tests: -points from QS 2 pixel x 2 pixel (2.8 Mm x 2.8 Mm), square region -ingression from QS disturbances that happen to be converging coherently towards the focus rather than emanating from it GONG2010/SOHO24

  7. Acoustic glories from NOAA 11045 07/02/2010 GONG2010/SOHO24

  8. HO2=1.5 Hquiet2 Saturation develops above H2=Hquiet2 Warning: 5 h observations ! GONG2010/SOHO24

  9. More properties of 5mHz seismic glories: • Contamination • Directionality • Beading GONG2010/SOHO24

  10. More properties: Contamination • Distribution of EG POW QS in the right region of QS • Appear to show slight/significant enhancements. • Contamination from the neighborhood by: • Glory-like emission from main AR • 6mHz seismic activity from surrounding plages GONG2010/SOHO24

  11. Acoustic glories from 06 June 2000 Directionality More seismic emitters along the arrow. GONG2010/SOHO24

  12. 00:43 UT 22:24 UT Beading NOAA 8179 15/03/1998 GONG2010/SOHO24

  13. Acoustic glories from NOAA 11046 14/02/2010 GONG2010/SOHO24

  14. Conclusions -seismic emitters are localized seismic sources with episodic temporal behaviour -only a few of these are enough to contaminate the region and produce glories at 5mHz how many? One emitters gives 1.5-5 QS POW) -extended glories 20-30 Mm -they prefer non/low-magnetic areas “well positioned” -acoustic glories surround only large, multi polar ARs -50% of the EG POW in emitters is incoherent noise -50% of the EG POW is coherent emission -wave generation -”mini” source waves are refracted and interfere with coming waves from the source: Khomenko, Collados 2009 -bead-like structure? Emission/generation mechanism GONG2010/SOHO24

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