A Global Structure of the Magnetic Flux Rope Observed in Interplanetary Space Fitted by A Torus-type Force-free Model

A large percentage of coronal mass ejections (CMEs) at 1 AU exhibit large and coherent internal field rotations characteristic to magnetic flux ropes (magnetic clouds). But the global structure of flux ropes, i.e., the length and the curvature of flux ropes along their axis, has not been clarified yet. In order to obtain a clue to this problem, we here examine a case where data from two spacecraft are available. In our previous paper ([4]), the magnetic field from the NOZOMI spacecraft was analyzed with a cylindrical flux rope model ([3]). In this paper, we applied a torus-type force-free field model ([7]) to the magnetic field data obtained by both NOZOMI and ACE on July 14, 2000. The results from our model fits show that a single large-scale magnetic flux rope with local curvature extended globally with the angular extent of ∼ 120◦ (seen from the sun) in interplanetary space. This picture is consistent with that in our previous work ([4]).