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Radio Observations of Solar Eruptions

Radio Observations of Solar Eruptions. N. Gopalswamy NASA/GSFC Greenbelt MD USA Solar Physics with the Nobeyama Radioheliograph Nobeyama Symposium Kiyosato Oct 26-29 2004. Thanks to …. Y. Hanaoka M. Shimojo K. Shibasaki H. Nakajima T. Kosugi S. Enome

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Radio Observations of Solar Eruptions

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  1. Radio Observations of Solar Eruptions N. Gopalswamy NASA/GSFC Greenbelt MD USA Solar Physics with the Nobeyama Radioheliograph Nobeyama Symposium Kiyosato Oct 26-29 2004 Kiyosato Oct 26-29, 2004

  2. Thanks to … • Y. Hanaoka • M. Shimojo • K. Shibasaki • H. Nakajima • T. Kosugi • S. Enome • Nobeyama staff who pleasantly provided all necessary support Kiyosato, Oct 26-29 2004

  3. Sun in Microwaves • Quiet Solar disk at 10,000 K (most pixels are at this temperature): QS • Small bright areas on the disk: active regions (AR), post-eruption arcades (AF) • Dark areas on the disk: Filaments (F) because Tb ~ 8000K • Bright regions outside the disk: Prominences (P) Tb ~8000 K>> optically thin corona (~200 K); Sometimes mounds consisting of AR loops (Tb > 10000K) • Dimming (deficit of free-free emission) can be observed in some limb events. • Prominences and filaments erupt as part of coronal mass ejections • 100s of eruptions documented on the NoRH web site • Selected references: Hanaoka et al., 1994; Gopalswamy et al., 1996; 1999; 2003; Hori et al. 2000; 2002; Kundu et al. 2004 P F AF AR F QS τff = 0.2∫f--2T-3/2n2dl >1 for n=1011 cm-3 T=8000 K, f=17 GHz and L >1 km Tb = T Kiyosato, Oct 26-29 2004

  4. Eruptions • Prominence/filament eruptions • (Jets) Kundu, Shimojo • (Blobs) Hori, Shibasaki • (Waves) White, Aurass • (Radio bursts) G. Huang • Slow Eruptions • Fast eruptions • CME-PE statistics • Implications to polarity reversal & GCR modulation Kiyosato, Oct 26-29 2004

  5. Prominence Eruption 1992 Jul 31 Hanaoka et al.1994 P CME SXT/AF - Post-eruption arcade in microwaves - Prominence, Post-eruption Arcade Consistent with Standard Eruption model (Carmichael (1964), Sturrock (1968), Hirayama (1974), Kopp and Pneuman(1976) – CSHKP) - No CME observations, but SXR Dimming Signature Kiyosato, Oct 26-29 2004

  6. Three-Part CME Gopalswamy et al, 1996, 1997 P 16 km/s 12 km/s AF 4 km/s Jul 10-11, 93 • - All features of a typical CME in X-rays and • Microwaves • Kinetic energy (5.1026 ) < thermal energy (6.1028) • Low-end CME • Helical motion of the prominence followed by • radial eruption • Recent examples of helical motion by Hori (2000) Kiyosato, Oct 26-29 2004

  7. Filament Eruption and Dimming Gopalswamy and Hanaoka, 1998 Final: 68 km/s Accel: 11ms-2 01:20 06:41 AF Kiyosato, Oct 26-29 2004

  8. Filament is CME CORE Direct comparison with CMEs became possible when SOHO data started pouring in MLSO He 10830 images Gopalswamy, 1999 Additional Core He10830 filament at17:54 UT slowly rises and reaches the limb by 00:03 UT (2/7)  tracked in microwaves as a prominence  becomes the CME core in white light Kiyosato, Oct 26-29 2004 Gopalswamy et al .98 GRL

  9. Post-eruption Arcade Yohkoh/SXT images showing the formation of a post-eruption arcade, which lasts for a day SXR Arcade after eruption larger volume involved than Indicated by filament 1-AU Magnetic Cloud Kiyosato, Oct 26-29 2004

  10. A Complex Filament Eruption LWS CDAW 2002 (Shimojo), Kundu et al. 2004 See also Hanaoka & Shinkawa, 1999 on covering of bright plage by erupted filament Kiyosato, Oct 26-29 2004

  11. Two CMEs? Kundu et al. 2004 7.25 Ro/hr Onset 04:49 Corrected:4:45 650km/s 50km/s Kiyosato, Oct 26-29 2004

  12. CME Collision: A slow CME is Deflected by a Fast one • Slow CME (290 km/s) overtaken by a fast CME (660 km/s) • The slow CME core deflected to the left from its trajectory Kiyosato, Oct 26-29 2004

  13. Acceleration likely caused by the impact of fast second CME Kiyosato, Oct 26-29 2004

  14. Microwave Observations of CME Initiation A very fast CME: 5 Rs in less than 30 min  > 2000 km/s Kiyosato, Oct 26-29 2004

  15. An Eruption viewed in microwaves Gopalswamy, Shimojo, Shibasaki, 2004 Kiyosato, Oct 26-29 2004

  16. Microwave Emission seems to be from the body of the CME 02:17 – 02:13 02:17 – 02:16 17 GHz 17 GHz 1635 km/s C2 C3 02:42 C2 02:30 Kiyosato, Oct 26-29 2004

  17. An Eruption viewed in microwaves 02:15 UT HXR 930 km/s Hudson et al. 2001 Nobeyama HXT Catalog Kiyosato, Oct 26-29 2004

  18. Microwave Source Evolution HXR Hudson et al 2001 Kiyosato, Oct 26-29 2004

  19. Similar to Moving type IV? 1600 km/s 2465 km/s C2 17 GHz 1925 km/s 73.8 MHz 1635 km/s Gopalswamy & Kundu 1992 - The Microwave Structure is either the CME itself or a substructure, but not the core. - Microwave spectrum (17 and 34 GHz) indicates nonthermal emission - Similar to moving type IV burst C3 Kiyosato, Oct 26-29 2004

  20. CMEs & Prominence Eruptions (PEs) : Statistical Studies • Most studies started with CMEs and found PEs to be the most common near-surface activity (Webb et al., 1976; Munro et al. 1979) • Reverse studies were rare. Hori et al. studied 50 NoRH PEs (2/1999-5/2000) and found a 92% association. (They required simultaneous availability of SOHO, Nobeyama and Yohkoh data) • A comprehensive study using all the PEs (226) detected automatically showed that 72% of all PEs were associated with CMEs (Gopalswamy et al. 2003a; 2004) Kiyosato, Oct 26-29 2004

  21. Height-Time Plots of All PEs Gopalswamy et al. 2003 • The height-time plots can be broadly classified as radial (R – 82%) and Transverse (T – 18%) • R events reached larger height (1.4Rs) compared to T events (1.19Rs) • Most R events (83%) were associated with CMEs; most T events (77%) were not. • 134/186 (72%) PEs had CMEs; 42 (22%) had no CMEs; 11 (6%) had streamer changes • The majority of Streamer change events were T events; the rest were low-height R events Kiyosato, Oct 26-29 2004

  22. Properties of Prominence Eruptions (PEs) with and without CMEs:non-CME PEs are slower, have mostly transverse trajectories, and the maximum height reached is rather small 1.20 Ro Without CMEs 22 km/s Without CMEs With CMEs 68 km/s With CMEs 1.40 Ro Kiyosato, Oct 26-29 2004

  23. 17 GHz Nobeyama 2001/08/29 Event: no CME LASCO LASCO/C2 images show no changes around the Time of Prominence Eruption Kiyosato, Oct 26-29 2004

  24. Streamer Change Most of these streamers Disrupted within a day. Kiyosato, Oct 26-29 2004

  25. Temporal Relationship of PEs and CMEs • The onset time differences close to zero. • CME onset times extrapolated to 1 Rs from extrapolating linear h-t plots Kiyosato, Oct 26-29 2004

  26. PE-CME Spatial Relationship Open circles  PEs during SOHO downtimes • Strong evidence for PE-CME association • Previously shown by Hundhausen (1993) for SMM CMEs During Solar Minima the global dipolar field is strong and guides eruptions PE CME Kiyosato, Oct 26-29 2004

  27. Non-radial motion • Prominence Eruption in the SE direction • Corresponding changes in the streamer • CME & Core position angle ~ 90 deg • Influence of the global field Gopalswamy, Hanaoka, Hudson 1999 Filippov, Gopalswamy, Lozhechkin, 2001 Kiyosato, Oct 26-29 2004

  28. CMEs & Prominences • High latitude (HL) prominence eruptions and CMEs during CR 1950-1990 (mid ’99 – early ’02) • N-S asymmetry (NHL ends in 11/00; SHL ends in 5/02) • These CMEs are not associated with sunspot activity Gelfreikh et al 2002 Kiyosato, Oct 26-29 2004

  29. N +++++ PCF - - - - + + + + E W - - - - + + + + + - - - - Kiyosato, Oct 26-29 2004 S

  30. Cycle 23 Arrows: Lorenc et al. 2003; Harvey & Recely, 2003; Gopalswamy et al., 2003 • HL Rate picks up when polar B declines • North polar reversal at the time of cessation of NHL CMEs • South polar reversal 1.5 yr later, again coinciding with the cessation of SHL CMEs • LL CME rate rather flat after a step-like increase • Consistent with the time of PCF disappearance Kiyosato, Oct 26-29 2004

  31. Cycle 21 • Solwind coronagraph on board P78-1 (corrected rates published by Cliver et al., 1994) • PCF: Webb et al. 1984; Lorenc et al. 2003 • KPNO mag data • CME cessation coincides with the polarity reversal Kiyosato, Oct 26-29 2004

  32. CMEs and GCR Modulation Gopalswamy 2004 Gopalswamy 2004 A<0 A>0 A>0 HL NoRH PE LL Lara et al. 2004 Moraal, 1993 Kiyosato, Oct 26-29 2004

  33. Concluding Remarks • NoRH has contributed profoundly to the study of CMEs by providing info on various aspects: CME initiation/acceleration, Post-eruption arcade, CME relation to global B • Clarified CME-PE relationship unambiguously • Contributed to the understanding of Polarity reversal and high-latitude Eruptions • Prom eruptions have implications to Sun-Earth connection as well as Sun-GCR connection • It will be great if NoRH can see a 22-yr cosmic ray modulation cycle Kiyosato, Oct 26-29 2004

  34. Polarity Reversal in Photospheric Field Kiyosato, Oct 26-29 2004

  35. When are the reversals? • HL streamer peak (Feb 2000) implies presence of HL closed structures.  reversal is not complete • HL streamer brightness declines significantly towards the end of 2000 – agrees with CME cessation Wang, Sheeley & Andrews, 2002 Kiyosato, Oct 26-29 2004

  36. A High-latitude CME & PCF Nobeyama Radio Prominence LASCO/C2 Kiyosato, Oct 26-29 2004

  37. Emission Mechanisms(n, T, B, Fnt) • Thermal Emission - Free-free (8000 K to 10 MK) - Gyroresonance (Active Regions) • Nonthermal • Gyrosynchrotron (incoherent) - Plasma emission (nonthermal electrons  plasma waves  radio emission at fp, 2fp) • Other coherent processes Kiyosato, Oct 26-29 2004

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