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Characteristics of Mode Parameters in the Source Regions of CMEs: A First Look

This study identifies CME source locations, analyzes mode parameters, and compares active regions to quiet regions, emphasizing the frequency, amplitude, width, and total power of CME-associated regions. The text focuses on solar activity during 1997-2003, utilizing ring-diagram procedures to study 44 events within a specified time frame to avoid systematic errors. Comparisons with quiet regions reveal relative frequency differences, power ratios, and more. Various areas for further study are suggested for a deeper understanding of CME behavior.

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Characteristics of Mode Parameters in the Source Regions of CMEs: A First Look

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  1. Characteristics of Mode Parameters in the Source Regions of CMEs: A First Look Sushanta C. Tripathy National Solar Observatory

  2. Outline • Identification of CME source locations • Case study of 2 individual CMEs • Summary and plan for future

  3. Procedure • CMEs are selected from the catalogue of Zhou et al. (2006) who have studied a total of 288 halo CMEs during 1997-2003 and have identified their source locations by associating the events with surface activity. • CMEs are associated with extended bipolar regions, trans-equatorial magnetic loops, trans-equatorial filaments and long filaments. • We use the standard ring-diagram procedure and analyze an area of 15x15 degrees in heliographic longitude and latitude covering 128x128 pixels giving a resolution of 0.03232 Mm–1 or 22.497 RΘ–1. • Each region is tracked for 1664 minutes • We have analyzed 44 events using the GONG+ data during 2001-2003 within 30º of the central meridian to avoid fore-shortening effect.

  4. The mode parameters of CME regions are compared with those of quiet region at the same latitude and in the same Carrington rotation to avoid errors arising from the systematic effects and foreshortening. • Compare mode Frequency, amplitude, width and total power

  5. CME associated with AR NOAA 10225 • CME associated with AR located at N22W12 (CR 1997, CR Long: 113º) on 021219 • First seen in C2 data at 22:06:00 • Magnetic activity Index (MAI): 97.6 Gauss • No Flare observed • Quiet region at same position on 021212 (CR Long 204) and MAI 2.7 Gauss

  6. CME source location: N22W12

  7. Active Region NOAA 9628 • Location: S22.5 E15 (CR Long: 292.5) on 23 March 2001 • MAI 146.3 Gauss • Compared with a quiet region at same latitude and at 0º longitude on 16 March 2001 with a MAI of 0.08 Gauss (CR Long: 45º)

  8. Comparison of 2 quiet regions

  9. Relative frequency differences f P1 P2 p3 CME region Active Region Av. error in each point 3.5 mHz ~ 10-4μHz 4.5 mHz ~ 10-3 μHz

  10. Ratio of the peak power CME region Active Region f P1 P2 p3 Av. error in each point 3.5 mHz ~ 0.05 4.5 mHz ~ 0.12

  11. From Rajaguru, Basu, & Antia (2001)

  12. Relative difference in half-width f P1 P2 p3 CME region Active Region Av. error in each point 3.5 mHz ~ 0.07 4.5 mHz ~ 0.13

  13. Relative difference in total power CME region Active Region

  14. CME associated with a Filament • CME associated with filament located at S25W18 (CR 1986, CR Long:231º) • First seen in C2 data on 020214 at 02:30 • MAI: 11.3 Gauss • Quiet region at CR Long 169º (020217), MAI 3.7

  15. Relative frequency differences f P1 P2 p3 CME region Active Region

  16. Ratio of the amplitudes A / A (Quiet) CME region Active Region f P1 P2 p3

  17. Relative differences in half-width f P1 P2 p3 CME region Active Region

  18. Ratio of the mode area A*Γ / A*Γ (Quiet) CME region Active Region f P1 P2 p3

  19. Temporal evolution of line-width in AR and CME regions

  20. CME1: N22 w12 CME2: S25w18

  21. f-modes: 2550 to 2750 μHz p-modes 3000-3500 μHz

  22. Summary • The widths of the peaks is a function of the frequency and the radial order ‘n’. For most CMEs, the widths are smaller implying longer life times. • The f- and p-mode frequencies of high degree modes are significantly larger compared to quiet regions if the CME is in active region. • The power in both f- and p-modes is lower in CME regions • The increase in mode frequency is monotonic in frequency while all other properties show more complex frequency dependence.

  23. Areas for Further Study • Look at ring diagrams produced over shorter time spans and/or smaller patches to isolate more transient features. • Look at magnetograms to see how MAI changes day-to-day to see if this explains daily variations • Look at flow maps and other fluid descriptors. • MORE STATISTICS

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