HR: 0800h
AN: SH31A-0228    [Abstracts]
TI: Relationship between CME initial speed and magnetic helicity of magnetic clouds
AU: * Sung, S
EM: sksung@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 838 Daedeok-dae-ro, Yuseong-gu, Daejeon, 305-348, Korea, Republic of
AU: Marubashi, K
EM: kmaru@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 838 Daedeok-dae-ro, Yuseong-gu, Daejeon, 305-348, Korea, Republic of
AU: Kim, K
EM: khan@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 838 Daedeok-dae-ro, Yuseong-gu, Daejeon, 305-348, Korea, Republic of
AU: Cho, K
EM: kscho@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, 838 Daedeok-dae-ro, Yuseong-gu, Daejeon, 305-348, Korea, Republic of
AU: Moon, Y
EM: moonyj@khu.ac.kr
AF: Kyung Hee University, 1, Seocheon-dong, Giheung-gu, Yongin, 446-701, Korea, Republic of
AU: Chae, J
EM: chae@astro.snu.ac.kr
AF: Seoul National University, San 56-1, Sillim-dong, Gwanak-gu, Seoul, 151-742, Korea, Republic of
AB: In order to understand the relationship between solar and interplanetary phenomena, we have examined the initial properties of coronal mass ejections (CMEs) and magnetic helicity of magnetic clouds (MCs) for 24 CME- MC pairs. MCs are fitted with the linear force-free cylindrical model to obtain MC parameters (orientation, size, magnetic field magnitude, impact parameter, chirality, etc). The relative helicity per unit length of MC is calculated by \frac{H_MC}{L}=\frac{4π B₀²}{α}\int₀^RJ₁²(α r)rdr. Comparing the square of CME initial speeds (V_CME²) with the magnetic helicities (H_MC, we find that there is a positive correlation between V_CME² and H_MC, and the linear correlation coefficient (CC) between the two parameters is 0.52. We obtain a better correlation (CC=0.61) for 17 events whose impact parameter (the shortest distance of the satellite to the MC axis normalized by MC radius) is less than 0.5. Considering that the magnetic force in a flux rope is intimately related to magnetic helicity, our result supports that the magnetic force is responsible for the CME eruption. From this result we suggest that the high speed CME is associated with large magnetic helicity.
DE: 2101 Coronal mass ejections (7513)
DE: 2111 Ejecta, driver gases, and magnetic clouds
DE: 7513 Coronal mass ejections (2101)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting