Exploring Interplanetary Small Flux Ropes: A Comprehensive Review

Magnetic small flux ropes (SFRs) in interplanetary space are small, transient structures that are abundant in the solar wind that are commonly identified by strong core fields associated with a bipolar field in one of the magnetic field components. We examine the statistical properties of SFRs near the equatorial plane across an extensive heliocentric distance range from 0.13 to 5.45 au, combining studies from PSP near the Sun all the way to Juno at Jupiter. Over the past decade, a multitude of SFR catalogs have been assembled from varied spacecraft data over this large distance range, using different datasets and disparate identification criteria. Assimilating results from these different inquiries has not been done before and is necessary in order to draw meaningful conclusions related to SFR origins and evolution over these distances. Despite these recent statistical studies, establishing clear trends is difficult due to inconsistent methods and the lack of standardized set of criteria used to identify SFRs between the different investigations. We review and consolidate the main findings of recent research, to shed light on the origin of SFRs by establishing trends in the SFR occurrence frequency, duration, and magnetic field evolution. By thus gaining a more coherent and comprehensive understanding of SFR formation and evolution, we make recommendations for future investigations at distinct heliocentric distance ranges from the Sun to Jupiter.