We estimate axial lengths of helical parts in magnetic clouds (MCs) at 1AU from the magnetic flux (magnetic helicity) conservation between solar active regions (ARs) and MCs with the event list of Leamon etal. Namely, considering poloidal magnetic flux (ΦP) conservation between MCs and ARs, we estimated L h in MCs, where L h is the axial length of an MC where poloidal magnetic flux and magnetic twist exist. It is found that L h is 0.01-1.25AU in the MCs. If the cylinder flux rope picture is assumed, this result leads to a possible new picture of the cylinder model whose helical structure (namely, poloidal magnetic flux) localizes in a part of a MC.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
- Sun: corona
- Sun: coronal mass ejections (CMEs)
- Sun: magnetic topology
- Terrestrial relations