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Examination of the influence of internal structure of Coronal Mass Ejections (CMEs)
Introduction
Materials/Tools
Conclusions
Abstract
References
What's Next ?
The main purpose of this research is to determine the influence of internal structure of Coronal Mass Ejec8ons (CMEs) on their propaga8on in the Heliosphere using WSA-‐ENLIL Cone Modeling1. The Integrated Space Weather Analysis System (ISWA) and Stereo analysis tool were used to obtain several CME parameters. The ENLIL Cone Model was used to run 90 simula8ons for different cavity parameters of CME internal structures. The rela8onship between the cavity and CME propaga8on 8me and Kp index was studied for 15 CME events. As expected, when the velocity of CME is higher than the ambient solar wind speed, CME with smaller cavity (more heavy ones) propagates faster than the same size CME with larger cavity (lighter CMEs). Quite naturally the opposite behavior is observed when the velocity of CME is less than the solar ambient wind speed. For fast CME velocity the Kp index tends to decrease as the cavity increases while for slow CME velocity the Kp index remains constant. This research is very important for improving model capability to forecast space weather.
[1] Odstrcil. "Distor8on of the Interplanetary Magne8c Field by Three-‐dimensional Propaga8on of Coronal Mass Ejec8ons in a Structured Solar Wind." Geophysical Research 104 (1999): 225-‐28. Print.
[2] Taktakishvili, Aleksandre, Odstrcil, and P. MacNeice. "Model Uncertain8es in Predic8ons of Arrival of Coronal Mass Ejec8ons at Earth Orbit." Space Weather 8 (2010): 1-‐9. Print.
[3] Taktakishvili, Aleksandre, Masha Kuznetsova, and Anc Pulkinnen. "Valida8on of the Coronal Mass Ejec8on Predic8ons at the Earth Orbit Es8mated by ENLIL Heliosphere Cone Model." Space Weather 7 (2009): 1-‐7. Print
A con8nua8on to this work would be to adjust addi8onal free parameters on the ENLIL Cone Model so that ones can see how these changes influence the propaga8on 8me of CMEs.
Fast vs Slow CME Events
The WSA-‐ENLIL Cone Modeling tool is 8me-‐dependent 3D MHD model of the heliosphere. Its inner radial boundary is located beyond the sonic point, typically at 21.5 or 30 solar radii2. This model is used to improve space weather forecas8ng. ENLIL uses several input parameters to model CME propaga8on 8me in the heliosphere of CMEs3. One of these parameters is the CME internal structure (cavity). This research was focused on analyzing 15 CME events, deriving their parameters and changing the cavity parameter to understand how this change influences the propaga8on 8me in order to improve space weather forecas8ng.
The results confirm that lighter CMEs with longer cavity adjust
easier towards the background wind condi8ons so slow CMEs are picked up by the wind and fast CMEs are decelerated by the wind. Three different Kp es8ma8ons were used for each event. For fast CME veloci8es the Kp index tends to decrease as the cavity increases while for slow CME veloci8es the Kp index remains constant. Therefore, the cavity parameter could play a key role on improving space weather forecas8ng.
Figure1: This plot shows the behavior of CME propaga8on hours versus cavity parameters of two events. The doged lines represent the actual propaga8on 8me according to the Advanced Composi8on Explorer (ACE) satellite. For the fast CME event, the cavity that best matched the actual arrival on Earth was 0.54.
These three plots show that for CME veloci8es, Kp index tends to increase as the cavity increases while for slow CME veloci8es, Kp index remains constant.
Absolute Arrival Time of 15 CME Events
García Burgos, Axel Embry Riddle Aeronau8cal University; Pulkkinen, Anc Catholic University of America (CUA); Taktakishvili, Aleksandre University of Maryland, Baltimore County (UMBC) and Odstrcil, Dusan George Mason University (GMU)
NASA Goddard Space Flight Center 15 Earth directed CME events were analyzed using the Integrated Space Weather Analysis System and the SOHO/STEREO
Analysis Tool.
MATLAB ENLIL Cone
Modeling SOHO/STEREO
Analysis Tool
Percentage change in propagation hours of 15 CME Events
Figure 2: Fast CMEs show larger difference in change (cavity=0, reference point) of propaga8on hours than slow ones.
Change in Kp index of 15 CME Events Cavity=0 Cavity=0.5
Cavity= rcav/r
r rcav CME
The following plots show the influence of CME internal structure (cavity) on arrival 8me of Earth directed CME events. The data points used to make these plots were
[0 0.1 0.3 0.5 0.7 0.9]
These three plots represent the influence of CME internal structure on the geomagne8c ac8vity (Kp index) for Earth directed CME events. It ranges from 0-‐9 and each plot shows the kp index for three different assume clock angles.
Figure 6: This plot shows the error in hours between the modeled CME propaga8on 8me and the actual propaga8on 8me according to the ACE satellite observa8ons.
Figure 3: Kp index assume clock angle 90° vs CME cavity parameters
Figure 4: Kp index assume clock angle 135° vs CME cavity parameters
Figure 5: Kp index assume clock angle 180° vs CME cavity parameters
CME Event la8tude longitude Rmajor (degree) Vcld (km/s) 2012-‐03-‐07 4 -‐23 65 1800 2012-‐07-‐12 -‐14 -‐9 53 1358 2011-‐07-‐28 0 15 24 1198
2012-‐03-‐09 20 0 45 1150
2010-‐04-‐03 -‐23 25 60 1071 2011-‐02-‐15 -‐20 15 35 920 2011-‐06-‐02 5 30 60 815 2011-‐06-‐21 28 1 34 812 2012-‐08-‐04 -‐10 -‐25 42 812
2010-‐08-‐01 34 17 52 790
2011-‐06-‐21 -‐19 25 39 766 2011-‐04-‐07 -‐5 -‐20 38 550 2011-‐06-‐14 16 5 24 487 2010-‐09-‐11 17 -‐15 36 453 2010-‐09-‐11 9 -‐1.30 33 336
Table 1: This table shows the parameters obtained with SOHO/STEREO Analysis Tool of 15 CME events
Table of CME events
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