  Small interplanetary magnetic flux ropes (SIMFRs) are often detected by space
satellites in the interplanetary space near 1 AU. These ropes can be fitted by
a cylindrically symmetric magnetic model. The durations of SIMFRsare usually
<12 h, and the diameters of SIMFRsare <0.20 AU and show power law distribution.
Most SIMFRs are observed in the typically slow solar wind (<500 km/s), and only
several events are observed with high speed (>700 km/s). Some SIMFRs
demonstrate abnormal heavy ion compositions, such as abnormally high He
abundance, abnormally high average iron ionization, and enhanced O7+ abundance.
These SIMFRs originate from remarkablyhot coronal origins. Approximately 74.5%
SIMFRs exhibit counterstreamingsuprathermal electron signatures. Given their
flux rope configuration, SIMFRs are potentially more effective for substorms.
SIMFRs and magnetic clouds havemany similar observational properties but also
show some different observations.These similar properties may indicate that
SIMFRs are the interplanetary counterparts of small coronal mass ejections.
Some direct bodies of evidence have confirmed that several SIMFRs
areinterplanetary counterparts of CMEs. However, their different properties may
imply that some SIMFRs haveinterplanetary origins. Therefore, one of the main
aims of future research on SIMFRs is to determine whether SIMFRs originate from
two different sources, that is, some events are formed in the solar coronal
atmosphere, whereas others originate from the interplanetary space. Finally, in
this study, we offer some prospects that shouldbe addressed in the future.
