The Cassini spacecraft completed 20 highly repeatable orbits during northern summer at Saturn, known as the F-ring orbits, of which 18 are considered in this study. The spacecraft traversed Saturn's magnetotail current sheet during each apoapsis pass between 16 and 22 Saturn radii over 2-day intervals and revealed a highly variable radial magnetic field from orbit to orbit. The solar wind and planetary period oscillations (PPOs) are significant sources of temporal variability in the Saturnian magnetosphere. PPOs refer to dual magnetic perturbation systems, one in each hemisphere, which have been observed to modulate the position and thickness of the magnetotail current sheet with a ∼10.7-hr periodicity. Thus, we employ a model which considers dual-modulation effects of the northern and southern PPO systems, together with a model of variable solar wind forcing on the magnetotail current sheet, to investigate their combined temporal effects on the radial magnetic field in the magnetotail. For all 18 F-ring orbits considered, the modeled radial fields show excellent overall agreement with the temporal variability in the large-scale structure of the observed radial fields (root mean square error <1.5 nT for 80% of the orbits). The amplitudes of the northern PPO modulations are well constrained between 0.3 and 0.5 Saturn radii, and they exceed the southern modulations by a factor of 1.3. The solar wind forcing is observed to be highly variable from orbit to orbit.

The Cassini spacecraft completed its final set of orbits known as the "Grand Finale" (Revs 271-292) around Saturn between April and September 2017, during which time the spacecraft passed through the previously unexplored region between Saturn and its main ring system (A-D) near orbit periapsis. The azimuthal magnetic field B ϕ observed during these periapsis passes reveals the presence of a temporally variable field-aligned current system (Dougherty et al., 2018) along magnetic field lines that equatorially map to the region between Saturn's upper atmosphere (∼1.03R S , 1R S = 60, 268 km) and its innermost ring (D-ring ∼1.11 to 1.24R S), henceforth the intra D-ring region. The B ϕ observations were variable from orbit to orbit, where each periapsis pass was 6.5 days apart, despite a largely repeatable spacecraft trajectory, highly

Characterizing the location of the outer boundary of the outer radiation belt is a key aspect of improving radiation belt models and helps to constrain our understanding of the mechanisms by which the source and seed electron populations are transported into the radiation belts. In this paper, we hypothesize that there are statistical differences in the electron distribution function across the radiation belt outer boundary, and thus analyze electron flux data from the THEMIS (Time History of Events and Macroscale Interactions during Substorms) satellites to identify this location. We validate our hypothesis by using modeled electron L* values to approximately characterize the differences between electron distribution functions inside and outside of the radiation belts. Initially, we perform a simple statistical analysis by studying the radial evolution of the electron distribution functions. This approach does not yield a clear discontinuity, thus highlighting the need for more complex statistical treatment of the data. Subsequently, we employ machine learning (with no dependence on radial position or L*) to test a range of candidate outer boundary locations. By analyzing the performance of the models at each candidate location, we identify a statistical boundary at ≈8 RE, with results suggesting some variability. This statistical boundary is typically further out than those used in current radiation belt models.

“We don’t live in a meritocracy, and to pretend that simple hard work will elevate all to success is an exercise in willful ignorance.” (Reni Eddo-Lodge wrote in her book “Why I’m no longer talking to white people about race” (Published by Bloomsbury, London, p. 79, ISBN: PB: 978-1-4088-7)). This echoes through the academic scientific community, and can be readily seen in the demographics of physics prize winners. Prizes are extremely influential in both projecting how a community is outwardly perceived and actively shaping the community through facilitating career advancement. But how can biases in the awards process be addressed? We do not pretend to have all the answers, nor is there a single solution, but in this perspective article we explore one pragmatic approach to tackling chronic underrepresentation in the space sciences when it comes to nominations for awards and prizes.