1 / 13

Solar wind effect on the propagation of CME-associated interplanetary shocks

Solar wind effect on the propagation of CME-associated interplanetary shocks. 김관혁 , 문용재 , 조경석 한국천문연구원. Sun-Earth Connection. Interplanetary (IP) space:. Near-Earth space/Earth ionosphere:. Solar wind (V, N)/IMF (B) variations. Compressed magnetosphere. IP shock+ Magnetic cloud.

sol
Download Presentation

Solar wind effect on the propagation of CME-associated interplanetary shocks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Solar wind effect on the propagation of CME-associated interplanetary shocks 김관혁, 문용재, 조경석 한국천문연구원

  2. Sun-Earth Connection Interplanetary (IP) space: Near-Earth space/Earth ionosphere: Solar wind (V, N)/IMF (B) variations Compressed magnetosphere IP shock+ Magnetic cloud Magnetic storms (Ring current) Substorms (Aurora) Atmospheric heating CME Time Averaged MP SW dynamic pressure Time Compressed MP ~500-800 km/s N > 10 /cc RC ~400 km/s N < 10 /cc ExB flows 15 10 5 5 Dawn-Dusk E field Geosynchronous orbit 10 Dst 15 Recovery Phase Main Phase

  3. Magnetospheric responses to interplanetary (IP) shocks on Nov. 26, 2000 ACE (~230 RE) B Bz Near-Earth Space ACE (~230 RE) N Vsw Near-Earth Space KAK (L ~ 1.3) ground station Earth Sudden commencement (SC) Sudden impulse (SI)

  4. Data and event selection • IP shocks identified from SC/SI at the Earth and by examining SW/IMF data at the ACE satellite during 2000-2002 (solar maximum). • SC/SI events identified from the 1-min SYM-H data. • IP shocks driven by halo/partial halo CMEs identified from SOHO/LASCO. • CME initial speeds and CME onset times obtained from the CME catalog [Yashiro et al., 2004] • 56 CME-IP shock (SC/SI) pairs. • The events are mostly selected from the published archival data in the CME-IP shock studies [Cane and Richardson, 2003; Manoharan et al., 2004].

  5. Empirical shock arrival (ESA) model [Gopalswamy et al., 2004] Empirical CME arrival model [Gopalswamy et al., 2001], based on aconstant IP acceleration a = 2.193-0.0054Vcme Empirical shock arrival model [Gopalswamy et al., 2004] Acceleration-cessation distance: 0.76 AU

  6. Constant (mean) IP acceleration in ESA model [Gopalswamy et al., 2001] a = 2.193-0.0054VCMEfrom Helios 1/PVO and P78-1 at ~0.6-0.9 AU during 1979-1984

  7. ESA model prediction and observed shock arrival times N = 56 events |DT|  12 hours (34 events) |DT| > 12 hours (22 events) 91% (31 of 34 events) in 400-1300 km/sec 34 (61%) events predicted within 12 hours from ESA model ESA model prediction

  8. Is there a systematic dependence of the IP shock travel time deviations from the ESA model? Examine the deviations of shock arrival times from ESA model (T = Tobs-Tmod) with respect to CME initial speed (VCME),IP shock speed (VSH), and solar wind speed (VSW) just before IP shock VSH Solar wind speed VSW Time

  9. Deviations (T =Tobs-Tmod) of shock arrival times from the ESA model (Tobs-Tmod) vs. VCME VCME: CME initial speed from SOHO/LASCO (Tobs-Tmod) vs. (VCME-VSH) VSH: IP shock speed observed at ACE (1 AU) (Tobs-Tmod) vs. (VCME-VSW) VSW: Solar wind speed just before IP shock at ACE (1 AU)

  10. Revised ESA model [Texp-Tmod = a + bVCME] ESA model vs. Observation 400  VCME 1300 km/s ~61% (34 events) of 56 events within 12 hours from perfect agreement ~80% (45 events) of 56 events within 12 hours from perfect agreement

  11. Revised ESA model [Texp-Tmod = a + b(VCME-VSH)] Revised ESA model [Texp-Tmod = a + b(VCME-VSW)] ~90% of 56 events within 12 hours from perfect agreement ~90% of 56 events within 12 hours from perfect agreement

  12. Summary-1 • We evaluated the empirical shock arrival (ESA) model [Gopalswamy et al., 2004], based on a constant IP acceleration, using 56 CME-IP shock (SC/SI) pairs during 2000-2002. • Out of 56 CME-IP shock (SC/SI) pairs, ~61% (34 events) were predicted within 12 hours from the ESA model. • Most of the events (91%, 31 of 34 events) within 12 hours were in a range of VCME of 400-1300 km/s. • We find a systematic dependence of the IP shock travel time deviations from the ESA model. • This systematic dependence indicates that the constant IP accelerationin the ESA model is not reasonably well applied for all VCME but for VCME in the range of 400-1300 km/s.

  13. Summary-2 • Revised ESA model using T vs. VCME, T vs. (VCME-VSH), and T vs. (VCME-VSW) regressions predicts ~80%, ~90%, and ~90% of 56 events within 12 hours from perfect agreement. • We suggest that further study of solar wind effect on the propagation of IP shock associated with slower (VCME < 400 km/s) and faster (VCME > 1300 km/s) CMEs is required to improve the prediction accuracy of the IP shock arrival times at 1 AU, which is the first step in space weather forecasting.

More Related