A multispacecraft study of a small flux rope entrained by rolling back magnetic field lines


We present a small flux rope (SFR) with smooth magnetic field rotations entrained by rolling back magnetic field lines around 1 AU. Such SFRs have only been seldom reported in the literature. This SFR was adjacent to a heliospheric plasma sheet (HPS), which is defined as a high plasma beta region in the vicinity of a heliospheric current sheet. Even though the SFR and HPS have different plasma beta, they possess similar plasma signatures (such as temperature, density, and bulk speed), density ratio of alpha particle-to-proton (Nα/Np), and heavy ion ionization states, which imply that they may have a similar origin in the corona. The composition and the configuration of the rolling back magnetic field lines suggested that the SFR originated from the streamer belt through interchange reconnection. The origin processes of the SFR are presented here. Combining the observations of STEREO and ACE, the SFR was shown to have an axis tilted to the ecliptic plane and the radius may vary with different spatial positions. In this study, we suggest that interchange reconnection can play an important role for the origin of, at least, some SFRs and slow solar wind.

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JGR: Space Physics



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