Authors: Sahanaj Aktar Banu (University of New Hampshire, Durham, New Hampshire, United States), Reka Winslow (University of New Hampshire, Durham, New Hampshire, United States), Emma Davies (GeoSphere Austria, Austrian Space Weather Office, Vienna, Vienna, Austria), Camilla Scolini (University of New Hampshire, Dover, New Hampshire, United States), Charles J Farrugia (University of New Hampshire, Durham, New Hampshire, United States), Noé Lugaz (University of New Hampshire, Durham, New Hampshire, United States), Nada Alhaddad (University of New Hampshire, Durham, New Hampshire, United States)

This study investigates the statistical properties of small flux ropes (SFRs) in the near-equatorial plane within a range of heliocentric distances from 1 to 5.44 au. Using magnetic field measurements acquired by the Juno spacecraft during its cruise phase, and strict identification criteria along with minimum variance analysis, we visually identify 338 SFRs occurring uniformly throughout the radial distances sampled by the spacecraft. The average duration of the events in our database is 122 minutes, with a minimum and maximum duration of 5 minutes and 465 minutes, respectively. Through superposed epoch analyses of SFRs binned by heliocentric distance, we find that the magnetic field profile of SFRs remains symmetric throughout our distance range, suggesting that the SFRs in our database likely do not expand during propagation. We also observe that the magnetic field profile of the SFRs observed close to heliospheric current sheet (HCS) crossings is more asymmetric than that of SFRs detected far from the HCS. This result suggests that SFRs may originate in interplanetary space through magnetic reconnection processes in the HCS, and quickly reach a relaxed state in pressure balance with the surrounding solar wind. Additionally, we find that the mean magnetic field of SFRs decays faster with heliocentric distance than the interplanetary magnetic field (IMF). Therefore, based on one of our identification criteria that the magnetic field magnitude inside SFRs has to be at least 1.3 times enhanced compared to the surrounding IMF, our results suggest that at these heliocentric distances, SFRs likely become indistinguishable from the IMF on short distance scales, when their magnetic field becomes comparable to or less than that of the IMF. Overall, our statistical findings favor an interplanetary, local origin of SFRs. We also find that their occurrence rate has a moderate anticorrelation with the yearly mean sunspot number and with solar activity, which is consistent with earlier studies.