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Microwave Signatures of Fast CMEs

Microwave Signatures of Fast CMEs. Nat Gopalswamy NASA Goddard Space Flight Center Greenbelt MD 20771 USA. Plan of study. Select all CMEs with speed > 1500 km/s for the period 1996-2005 Look for eruptive and flare signatures If eruptive, compare kinematics from NoRH and LASCO

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Microwave Signatures of Fast CMEs

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  1. Microwave Signatures of Fast CMEs Nat Gopalswamy NASA Goddard Space Flight Center Greenbelt MD 20771 USA Nobeyama radioheliograph visit

  2. Plan of study • Select all CMEs with speed > 1500 km/s for the period 1996-2005 • Look for eruptive and flare signatures • If eruptive, compare kinematics from NoRH and LASCO • Distinguish disk and Limb Signatures • Make new images if needed Nobeyama radioheliograph visit

  3. Motivation • Fast and Wide CMEs important for space weather • Identifying a microwave signature may be a useful tool to characterize these CMEs Nobeyama radioheliograph visit

  4. Initial set of fast events (speed V > 1500 km/s) to look for Microwave activity (38 events in Nobeyama Time Window) ----------------------------------- CME first appearance V(km/s) Preliminary Survey ----------------------------------- 1998/03/31 06:12:02.000 1992 1998/04/23 05:27:07.000 1618 One frame shows eruption 5:46:20 east limb 1998/05/09 03:35:58.000 2331 03:36 - 04:26 west limb 1998/06/04 02:04:45.000 1802 NW limb NoRH PE at 1:36 (not in catalog), EIT dimming 1:58 2000/05/12 23:26:05.000 2604 NoRH Data gap? 2000/11/08 23:06:05.000 1738 double eruption (GRL), two NORH AFs 2000/11/25 01:31:58.000 2519 NE quadrant appearance of an elongated feature before flare 2001/04/03 03:26:05.000 1613 something disappears bet 3:05 &3:25 above AR EIT dim3:05 2001/04/05 02:06:06.000 1857 (narrow) diffuse behind the limb? Flare in the east 2001/04/10 05:30:00.000 2411 disk event 2001/04/18 02:30:05.000 2465 well studied. 2001/05/30 00:06:07.000 2087 PE (not cataloged) 00:00 to 00:20 east limb 2001/06/11 04:54:05.000 1647 (narrow 37 deg) 3:50-4:10 nonradial ejection? 2001/08/15 23:54:05.000 1575 backside nothing in NoRH obvious 2001/11/25 23:06:54.000 1574 onset before NoRH obs start 2002/04/21 01:27:20.000 2393 studied 2002/05/22 03:50:05.000 1557 interaction event; cataloged; need shifted HR images 2002/05/30 05:06:05.000 1625 EIT at 4:48; 4:55 noRH brightening 2002/07/23 00:42:05.000 2285 rhessi HR images available? 2002/08/24 01:27:19.000 1913 good event HR images needed 2002/09/27 01:54:05.000 1502 SW narrow; eruption at 1:30 SW 2002/10/27 23:18:13.000 2115 two events? this CME source is backside? EIT 304 2002/11/10 03:30:11.000 1670 ejecta at 3:20 SW 2003/01/22 23:54:05.000 1855 (jet) poor images 2003/05/31 02:30:19.000 1835 no EIT westward extension 17 GHz at 2:38; changes ~2:20 SW 2003/06/02 00:30:07.000 1656 eruption 00:00 to 00:10? 2003/06/15 23:54:05.000 2053 change at~23:10 above east limb; elongation of 17 Ghz at 23:56 2003/06/17 23:18:14.000 1813 flare started before obs. start 2003/10/31 04:42:50.000 2126 (narrow) PE 4:40 - 5:00 not cataloged 2003/11/09 06:30:05.000 2008 backside east limb 2004/01/07 04:06:07.000 1581 PE 4:10-4:40; first brightening at 3:50 2004/01/08 05:06:05.000 1713 elongated feature disappears near AR after brightening; same AR 2004/04/11 04:30:06.000 1645 SW quad 4:00-4:10 ejection 2004/11/10 02:26:05.000 3387 NW quad EW arcade 2005/01/15 06:30:05.000 2049 NNW quad bright arcade 2005/01/15 23:06:50.000 2861 bad images 2005/07/27 04:54:05.000 1787 4:30-510 PE not cataloged 2005/07/30 06:50:28.000 1968 PE not cataloged? --------------------------------------------------------- Nobeyama radioheliograph visit

  5. Related issues Nobeyama radioheliograph visit

  6. Extend the PE-CME Relationship to 2005 Nobeyama radioheliograph visit

  7. Low Frequency Type II Bursts, CMEs, and Space Weather Nat Gopalswamy NASA Goddard Space Flight Center Greenbelt MD 20771 USA Observing metric type II bursts alone is not enough to track CMEs into the Heliosphere Nobeyama radioheliograph visit

  8. Why Study Low-frequency Type II Bursts? • Among solar radio bursts, type II bursts are important for space weather because they help remote-sense large-scale mass motion • Type II bursts at decameter-hectometric (DH) and longer wavelengths are indicative of fast and wide CMEs that are geoeffective & SEPeffective • SEP events due to CME-driven shocks & geomagnetic storms happen when CMEs impinge on Earth’s magnetosphere • Type II bursts are also indicative of large-scale interplanetary disturbances that may impact other locations in the heliosphere (e.g. at and enroute to Mars) Nobeyama radioheliograph visit

  9. Sources of Geoeffective & SEPeffective CMEs N 37/55 = 67% 18/55 = 33% 15W SEP E W S ODst < - 200 nT O - 300nT < Dst < - 200 nT O Dst < - 300 nT Type II bursts can detect both of these populations Nobeyama radioheliograph visit

  10. Coronal (1947) Interplanetary (1973: Malitson et al.) SOHO/LASCO FOV 2-32 Rs Ionospheric Cutoff 20 214 Rs 2.5 1.5 Gap filled by Wind/WAVES At Decameter-Hectometric (DH) Wavelengths (Bougeret et al. 1995) Type II, Type III bursts Type III storms are observed in the IP medium Some type IV less complex Nelson & Labrum, (1985) Nobeyama radioheliograph visit

  11. 800 kHz 8.56 Ro 2005/09/10 22:37 UT CME 1893 km/s PA120 • Very intense type II radio bursts: Shock-driving capability of CMEs. • 1-14 MHz crucial because the associated CMEs just leave the Sun • Sky-plane height of the CME is ~9 Ro “The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below ~4 MHz; such emissions were previously called IP type II events.” Cane & Erickson 2005 Nobeyama radioheliograph visit

  12. IP type II bursts “The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below ~4 MHz; such emissions were previously called IP type II events.” “… metric type II bursts, unlike IP type II events, are not caused by shocks driven in front of CMEs.” Cane & Erickson 2005 Nobeyama radioheliograph visit

  13. A DH Type II & its CME Type II starts at the edge of C2 FOV 3.98 Rs 15.58 Rs 22.21Rs CME at edge of C3 FOV (30 Rs) 2.86 Rs f =0 .85MHz fp = 0.425 MHz n = 2.2x103 cm-3 when the CME is at 30 Rs Vcme ~ 770 km/s Radio emission tracks CME beyond LASCO FOV No Type II yet Nobeyama radioheliograph visit

  14. DH Type II (no m) Type II in variousWavelength Ranges Metric Type II m-km Type II (m not shown) m f DH km km type II t DH Type II Observed type II features: m – pure metric (ground); DH-decameter-hectometric; km – kilometric; some start at m and go all the way to km (m-to-km) Nobeyama radioheliograph visit

  15. Type II Bursts Organized by CMEs Speeds, widths & deceleration of CMEs progressively increase for metric, DH, full-range (m-to-km) Type II Bursts, compared to the general populationPurely km type IIs due to accelerating CMEs, which form shocks far away from the Sun m DH km Nobeyama radioheliograph visit

  16. m DH km Properties of CMEs associated with m, DH and m-to-km type II’s compared to those of all CMEs m-to-km (mkm) CMEs similar to SEP-producing CMEs km CMEs similar to metric CMEs, but acceleration is different Nobeyama radioheliograph visit

  17. SEP & m-to-km Events • Similar number of SEP and m-to-km events  same shock accelerates electrons and protons • Difference due to connectivity for particle and wider beam for bursts • 33.8% of m-to-km events to the east of W10; only 13.8% of SEP events to the east of W10 Nobeyama radioheliograph visit

  18. SEP Release height Leading edge of the CME at the time of GLE release Nobeyama radioheliograph visit

  19. IP Shocks & Type IIs Close similarity between rates of SEP events, IP type II bursts & in situ shocks Electron and proton acceleration by the same shock Nobeyama radioheliograph visit

  20. CMEs Relevant for Space Weather electron Acceleration (CME shock) proton Acceleration CME shock Plasmag Impact CME CMEs of heliospheric consequences V1000 km/s Nobeyama radioheliograph visit

  21. Characteristic Speeds “1980s view” of Alfven speed Region 1: Difficult to make Type II bursts – explains Type II starting f ~150 MHz Region 2: Easy to make Type IIs below 2.5 Ro (m) Region 3: IP medium – Very Fast CMEs & accelerating CMEs produce type II Krogulec et al 1994 Mann et al. 1999 Gopalswamy et al. 2001 Nobeyama radioheliograph visit

  22. Occurrence Rates • 10% of CMEs & 5% of flares have type IIs • m type IIs most abundant • m type IIs 2-3 times more abundant than IP type IIs Nobeyama radioheliograph visit

  23. Starting frequency & CME height Type II behind CME leading edge Type II & CME in different directions IP and metric drift rates can be Different if the acceleration Initially occurs in the Qperp region and later (IP) in the Q|| region (Holman & Pesses,1983) Nobeyama radioheliograph visit

  24. Flank NOSE Flank Two possible Type II Locations • Flanks: Lower Alfven speeds expected. For a given CME speed, there may be a shock at the flanks, while no shock at the nose • Shock may be Quasiperp at the CME flanks while quasiparallel at the nose Nobeyama radioheliograph visit

  25. m-to-km Type II bursts and Space Weather • Less than 1% of the 9000 CMEs observed during 1996-2004 were associated with the m-to-km type II bursts. • Therefore, the m-to-km bursts can isolate the small fraction of CMEs that are likely to have significant impact on the inner heliosphere • It takes typically about an hour for the disturbances to reach km level • Very useful for ESPs and SSCs • Maybe useful for SEPs Nobeyama radioheliograph visit

  26. 2005 Jan 17 AR 720 Nobeyama radioheliograph visit

  27. Interaction Event 2548 km/s 2094 km/s Nobeyama radioheliograph visit

  28. Summary • The speed and width of CMEs progressively increase in the following order: general population, metric-associated, DH-associated m-to-km-associated • m-to-km CMEs similar to SEP-producing • m-to-km type IIs probe the entire Sun-Earth connected Space and the energetic CMEs propagating throughout this region. • They can predict shocks of significance to Earth and other destinations in the heliosphere • m type IIs alone cannot tell whether the CMEs are geoeffective. They need to have IP counterpart. Nobeyama radioheliograph visit

  29. Additional Comments • Imaging the type IIs is ideal (SIRA) • Otherwise, at least we need direction finding at sufficiently high frequencies (above 1 MHz) • The lower sensitivity at higher frequencies is one thing that needs to be avoided • RPW should be able to measure shock strength when the shock is still closer to the Sun Nobeyama radioheliograph visit

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