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Modeling of CME-driven Shock propagation with ENLIL simulations using flux-rope and cone-model inputs Using observations from STEREO/SECCHI and SOHO/LASCO,

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Presentation on theme: "Modeling of CME-driven Shock propagation with ENLIL simulations using flux-rope and cone-model inputs Using observations from STEREO/SECCHI and SOHO/LASCO,"— Presentation transcript:

1 Modeling of CME-driven Shock propagation with ENLIL simulations using flux-rope and cone-model inputs Using observations from STEREO/SECCHI and SOHO/LASCO, combined with WSA-Cone-ENLIL model simulations, we study the propagation and evolution of 17 CME-driven shock from Sun to Earth. We use flux-rope (FR) and cone-model fitting outputs of V cme and width as spherical cloud speed and angular width inputs for the ENLIL model. We compared the simulated the shock arrival times T enlil from two sets of inputs with the observed shock time by Wind T obs. The results show that the predictions from ENLIL using FR-fit inputs are generally better those using cone- model fit inputs. However, both model inputs give decent prediction results. Overall, the FR-model fit to multi-view observations provides more accurate values of CME actual speeds and widths. There is no significant differences between the mean fit CME speed and width from two models. The difference of the mean speed and the mean width from two models are 45 km/s and 5°, respectively, and the mean prediction errors for the FR and cone-model are 5.4 hours and 6.1 hours. It is found that for the slow CME with speeds < 900 km/s, the mean prediction errors are improved to 4.1 hours (FR-fit) and 5.0 hours (Cone-fit) with dcld = 2 ( density enhancement factor of cloud to fast solar wind) compared to default dcld of 4. In addition, we study the predictions from the kmTII method, which is based on the kilometric Type II radio emissions measured by Wind/WAVES (Cremades, et al., 2007). It is found that the kmTII predictions can be improved by using the ENLIL model plasma density upstream the modeled CME/shock (compared to using the average density at 1 AU of n 0 = 7.2 cm -3 ). H. Xie 1,2, C. St Cyr 2, N. Gopalswamy 2, and D. Odstrcil 2,3 1 Catholic University of America, Washington, D.C.; 2 NASA-GSFC; and ; 3 George Mason University Difference of prediction error:  err = |Err_FR – Err_cone| as function of input speed difference  V fit = |Vfr - Vcone|:  err = ~ 2.27+ 0.01*  V fit. In average, an input CME speed difference of 100 km/s results in a prediction error difference of 3.46 hours. Note that, however, relatively large scattering exists for individual events. The selected event list includes earthward halo CMEs from 2010 to March 2012 with Vcme > 500 km/s. The table lists the shock date and time, CME date and time, source location, FR-fit and cone-fit speed and half width, ENLIL prediction error with two model fits: Err_f and Err_c, dcld, and the kmTII prediction errors for six kmTII CMEs, Err_km1 and Err_km2, using the ENLIL model density, n0_enlil, and the average solar wind plasma density, n0_avg, at 1 AU respectively. The mean Err_km1 = 4.88 hrs and mean Err_km2 = 6.0 hrs. Top panels show that the mean cone-fit CME speed Vcone is slightly larger than the mean FR-fit speed Vfr but max( Vcone – Vfr ) can reach 601 km/s. Bottom panels show that the mean half width  cone is slightly larger than  fr and max(  cone –  fr ) = 13 . Prediction error DT= Tenlil-Tobs. Overall, the errors using cone-model fit inputs (Err_cone) are larger than those using FR-fit inputs (Err_FR). Comparison of Cone-model and FR-model fitting: V sky vs. V fit. Red and blue diamonds denote Vfr and Vcone, over- plotted with solid line V fit =V sky. Where V sky and V fit are the sky-plane speed and model fit Speed of the CMEs. Type II dynamic spectrum detected by the Wind/Waves on January 23 2012. Red cross symbols in the figure mark the heights from COR2 observations and the ENLIL simulation results, with a simple density model n = n 0 /r 2 (n 0 is the plasma density at 1 AU in units of cm −3 ) we have r(t) = (9/18)sqrt(n 0 )/f(t), r(t) in units of AU. White X symbols are selected measurement points in the spectrum, with which we derive the shock speed to predict the shock arrival time: Vsh = (9/18) sqrt (n 0 ) × slope(1/f) × 1.5e8 (km/ s). ShkdateTimeCMEdateTimeLoc_scFR-fitCone-fitErr_fErr-cdcldErr_km1Err_km2 Vw/2V (n0_enlil)(n0_avg) (UT) (km/s)(deg)(km/s)(deg)(hr) 2 02/11/1000:0002/07/1002:45N21E115253958052-10.9-14.472 n/a 04/05/1007:5804/03/1010:34S25W03101137914410.736.872 n/a 02/15/1017:2802/12/1011:50N21E0775238791400.651.742 n/a 04/11/1012:1804/08/1003:15N24E166293065637-4.51-6.942 n/a 05/28/1002:0005/24/1013:05S15W186503861148-8.16-52 n/a 02/18/1100:4002/15/1102:36S21W186514162449-3.78-2.262 n/a 06/23/1102:1806/21/1102:05N16W001031361211396.922.424 n/a 07/11/1108:0507/09/1100:15S17E207513992239-1.47-5.384 n/a 08/04/1121:1008/02/1106:05N14W01100140109942-5.52-10.14 n/a 08/05/1117:2308/04/1104:05N19W361722501556471.33-0.564-8.22-3.92 09/09/1111:4909/06/1122:22N14W1810334583239-5.990.424 2.847.99 11/12/1105:1011/09/1113:21N26E43128838123944-3.02-6.814 n/a 01/22/1205:3301/19/1213:44N33E27132740149448-4.1-6.554 3.779.99 01/24/1214:3501/23/1203:38N33W212002502456533.91-2.524 -5.71-0.42 03/08/1210:3003/07/1200:02N17E272349402950493.78-5.084 1.8712.79 03/11/1212:2903/09/1203:22N17W03128143116853-4.46-3.214 n/a 03/12/1208:3003/10/1217:15N17W241705441378490.65.174 -6.91-0.94


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