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High-Cadence EUV Imaging, Radio, and In-Situ Observations of Coronal Shocks and Energetic Particles: Implications for Pa

This study explores the detection and characteristics of coronal shocks and their role in accelerating and releasing energetic particles in the solar corona. The research combines high-cadence EUV imaging, radio observations, and in-situ particle measurements. The findings provide insights into particle acceleration mechanisms and have implications for space weather forecasting.

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High-Cadence EUV Imaging, Radio, and In-Situ Observations of Coronal Shocks and Energetic Particles: Implications for Pa

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  1. High-Cadence EUV Imaging, Radio, and In-Situ Observations of Coronal Shocks and Energetic Particles: Implications for Particle Acceleration K. A. Kozarev1,2, K. E. Korreck2, V. V. Lobzin3, M. A. Dayeh4, R. Ebert4, M. A. Weber2, N. A. Schwadron5 (1) Boston University, Boston, MA, USA (2) Smithsonian Astrophysical Observatory, Cambridge, MA, USA (3) University of Sydney, Sydney, Australia (4) Southwest Research Institute, San Antonio, TX, USA (5) University of New Hampshire, Durham, NH, USA 2011 EGU General Assembly, April 6, 2011 Vienna, Austria

  2. Outline - Background - The June 12 and 13, 2010 events     - Observations     - Interpretation - Conclusions - Future work

  3. Outline - Background - The June 12 and 13, 2010 events     - Observations     - Interpretation - Conclusions - Future work

  4. Background - Energetic particles accelerated and released by mechanisms related to flares and CMEs in the solar corona; Shocks of particular interest. - Remote observations of coronal shocks have been difficult, due to limited spatial and temporal coverage. Main problem was time cadence. - The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) provides ultra-high cadence observations of coronal EUV phenomena; • Main questions: 1. Can coronal shocks be detected with EUV observations? 2. If so, what can we learn about their efficiency in accelerating/releasing particles into the heliosphere. - Ultimate goal - identify remote EUV wave observables that can be used in modeling and predicting SEP fluxes at 1 AU; • This study: Characterize two EUV off-limb waves, attempt to relate wave/shock signatures to particle production and release.

  5. Atmospheric Imaging Assembly (AIA)‏ image: http://sdowww.lmsal.com/suntoday/

  6. Atmospheric Imaging Assembly (AIA)‏ logT~6.3 logT~6.1

  7. Outline - Background - The June 12 and 13, 2010 events     - Observations     - Interpretation - Conclusions - Future work

  8. June 12, 2010 – AIA base difference movies AIA/193 Angstrom AIA/211 Angstrom

  9. June 13, 2010 – AIA base difference movies AIA/193 Angstrom AIA/211 Angstrom

  10. June 12 and 13, 2010. Remote Observations by SDO/AIA and Learmonth Observatory - Fast coronal waves observed in 193 and 211 Angstrom by AIA; Waves seen over ~5 minutes in AIA field of view. - Wavefront positions measured along radial profiles. - Simultaneous emission of metric radio type II bursts - attributed to shock-accelerated electrons Kozarev et al., submitted to ApJ Letters

  11. Wave and shock positions from EUV and radio - EUV wavefront 'nose' positions - shock positions from type II emission, assuming a Newkirk electron density model

  12. EUV and radio kinematics

  13. Thermal and density response of June 13 wave - Performed differential emission measure (DEM) analysis on four regions before and during the June 13 EUV wave - Solutions from two regions significant (R2, R3)‏ - No significant change in temperature profiles, increase of emission measure during wave - Brightening due to density increase - Density ratios - r > 1.12 - Wave possibly a weak shock

  14. Proton observations – GOES and SOHO

  15. Particle observations – STEREO Behind Ahead CIR Figure: STEREO Science Center

  16. Multipoint particle observations – STEREO and ACE High Fe/O - impulsive Shock? CIR

  17. Outline - Background - The June 12 and 13, 2010 events    - Observations     - Interpretation - Conclusions - Future work

  18. Relevance of magnetic geometry for particle production and release PFSS field lines overlaid on SDO/AIA images

  19. Wave and shock positions from EUV and radio - EUV wavefront 'nose' positions - shock positions from type II emission, assuming a Newkirk electron density model

  20. June 12 and 13, 2010 events:  Interpretation - Coronal EUV waves on both days associated with type II radio bursts. - No clear driver on June 12. - CME driver seen on June 13. - DEM analysis shows wave related to a slight density jump r~1.12. - Propagation through model magnetic fields agree with radio emission locations: open geometry and lateral propagation source on June 12, closed geometry and electron acceleration at the shock nose on June 13. - Detection of impulsive protons and electrons from June 12 event up to 50 MeV reached ACE and STEREO-A right away; STEREO-B saw a CIR during both events. - Further impulsive particle detections at low energies related to June 13 event at ACE/GOES and STEREO-A. - IP shock possibly related to June 13 event arrived at STEREO-A on June 14.

  21. Conclusions - EUV wave signatures related to coronal shocks - Weak driven coronal shock observed during June 13 event - Magnetic geometry important for particle production/release - Impulsive in situ particle fluxes seen during both events - EUV remote observations potentially helpful in characterizing energetic particle production and release in the solar corona!

  22. Future Work - Perform onset analysis of in situ particle observations for the June 12 and 13, 2010 events - Improve EUV wave detection and kinematic measurements algorithms: limit human interaction - Expand the magnetic geometry analysis to identify shock-to-field angles and shock particle acceleration efficiency - Analyze additional events with EUV, radio, in situ observations

  23. Thank You!

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