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Solar Wind Composition: Identifying Solar Sources and Flow Types

This study focuses on using solar wind composition as a tool to identify different solar sources and types of solar wind, including coronal hole-associated high-speed streams, ICMEs, and slow solar wind. The study also explores the use of composition in identifying boundaries in large-scale structures. The results are subject to revision as the work is in progress.

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Solar Wind Composition: Identifying Solar Sources and Flow Types

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  1. STEREO PLASTIC Composition at Solar Wind Interfaces Toni Galvin (UNH) K. Simunac (Protons), A. Gustafson (Programs), Lorna Ellis (Data, Programs), M. Popecki (Calib), K. Singer (Calib), R. Karrer (Calib), the PLASTIC Team, and E. Huttunen (Flux Rope) STEREO PLASTIC Institutions: UNH, U Bern, MPE, U Kiel, NASA/GSFC IDPU/LVC provided by UCB (IMPACT) The Sun in EUV courtesy STEREO/SECCHI/NRL STEREO SWG Meudon France April 21 2008

  2. Solar Wind Composition • As a tool in identifying solar sources and types of solar wind (coronal hole-associated high speed streams, ICMEs, slow solar wind) • As a tool in identifying boundaries in large scale structures

  3. Solar sources for the high speed solar wind - long lived polar and equatorial coronal holes - observed by SECCHI EUVI (B). Solar sources for slow solar wind is an area of discussion -- likely multiple sources, including small transients.

  4. Solar wind M/Q composition as a tool in identifying flow types C O Fe Fe Si M/Q distributions for fast vs. slow solar wind, von Steiger et al. 2000 300-day accumulations each trace Fe M/Q distributions for different types of solar wind, Ipavich et al. 1992 3-month interval

  5. Solar wind M/Q composition as a tool in identifying flow types and solar sources ICME Fe High Q (low M/Q) Fe C O Slow Wind CH Fast Wind Fe Low Q (high M/Q) Fe Si Fast Wind M/Q distributions for fast vs. slow solar wind, von Steiger et al. 2000 300-day accumulations each trace Fe M/Q distributions for different types of solar wind, Ipavich et al. 1992 3-month interval

  6. Solar Wind Interfaces Slow-Fast-Slow Interfacesin corotating structures Ambient-ICME-Ambient Interfaces Pizzo, V., J. Geophys. Res., 83, 5563–5572 (1978).

  7. Solar wind composition as a tool in identifying interfaces between different solar wind flows Many studies on composition at Slow/Fast interface. Fewer studies on Fast/Slow interface (Burton et al.1999)

  8. Composition with STEREO PLASTICNOTE: work in progressresults subject to revision !

  9. PLASMA AND SUPRATHERMAL ION COMPOSTION INSTRUMENT • Solar Wind Sector (SWS) Small (Proton) Channel measures the distribution functions of solar wind protons (H+) and alphas (He+2), and can include M/Q ~ 2, such as O+8, C+6. • Solar Wind Sector (SWS) Main (Composition) Channel measures the more abundant solar wind heavy ions (e.g., C, O, Mg, Si, and Fe). Solar Wind Sector Small Main PLASTIC Wide Angle Partition for Suprathermals

  10. O Fe He+ pickup ions He2+ H+ 78 keV/e 1 keV/e sweep • PLASMA AND SUPRATHERMAL ION COMPOSTION INSTRUMENT Switch from MAIN to SMALL channel typically in m/q region of He2+ Solar Wind Sector Small Main ESA EQ STEPPING PLASTIC Wide Angle Partition for Suprathermals

  11. Solar Wind Sector PRIORITY 2 Composition M/Q ~ 2 (CNO high charge states) Fe Relative Mass Mg/Si CNO Small Channel Main Channel Relative M/Q Relative M/Q

  12. Fe For Charge State Distributions - take a slice in “Mass” around the iron, and look at charge states over 1 hr accumulations

  13. >16 Fe Charge States Hour of Day (1hr bins)

  14. ICME Case Study Ambient-ICME-Ambient Interfaces STEREO A May 22-23 2007

  15. ICME Signatures in the Solar Wind Important note: Not all signatures are seen all the time… Shock, other discontinuities Counterstreaming suprathermal electrons (along the B field) Counterstreaming suprathermal protons (along the B field) Change in SEP intensity at discontinuity He/H enhanced Anomalous ion charge states (He+, Fe>16) Mass or FIP dependencies on elemental composition Low proton and electron kinetic temperatures Low plasma beta (gas pressure / field pressure) Strong B field Low B variance Field rotation (flux rope) Magnetic Clouds are a particular subset of ICMEs with distinct characteristics from the above list … strong magnetic field with a smooth and coherent rotation, low beta plasma with depressed kinetic temperatures

  16. May 22-23 2007 - Flux Rope Case Study IMPACT SWEA/MAG PLASTIC protons (Plot from E. Huttunen) Top: SWAVES May 19 2007 Bottom: SWAVES May 20 2007

  17. STEREO A a a b c d e Main Small b c e IMPACT and PLASTIC d Mass M/Q M/Q

  18. Highest Fe Charge State signature between lines 2 - 3. Still somewhat elevated after line 3 to end of day. Low Density Low Density May 23 May 24 May 20 May 21 May 22

  19. Slow-Fast-Slow Case Study STEREO A May 06-15 2007 Slow-Fast-Slow Interfacesin corotating structures

  20. Solar Wind Interfaces (Slow-Fast-Slow) perspective from STEREO PLASTIC proton and IMPACT magnetic field data May 6 - 14 2007 (from Simunac et al. this meeting)

  21. Perspective from Solar Wind Fe charge states: Example: 1 Day Fe Ionic Charge Q bins vs. Time bins (1hr) But for slow/fast/slow interfaces want several days overview …. Same format as before, but switched from IDL to Excel

  22. Solar Wind Fe Charge States

  23. Solar Wind Fe Charge States Shift to lower <Q> Fe Counts Fe Q -->

  24. Average <Q_Fe> and Fe+11 Speeds

  25. Proton and Fe+11 Speeds

  26. Charge Changes and Speed Differentials

  27. Solar Wind Sector PRIORITY 2 Composition M/Q ~ 2 (CNO high charge states) Fe Relative Mass Mg/Si CNO Small Chn Main Chn Relative M/Q Relative M/Q

  28. Interface from Slow to Fast - Changes in Heavy Ion Composition Abundances May 10 0-2UT May 6 0-2UT Possible shock May 8 22-24UT May 7 0-2UT SWS Heavy Ions “PR2” Two Hour Snap Shots

  29. Work in Progress! Still working on calibration factors for fine-tuning charge identifications (“fractional charge states”), and for possible systematic (E/Q calibration) affects on heavy ion speeds. Need to cross check Delta Speeds with Alfven Speeds

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