Magnetopause magnetic reconnection during periods of northward interplanetary magnetic field (IMF) plays a key role in the entry of solar wind mass into the magnetosphere. The effects of reconnection can be observed in the low-altitude cusp, and the new NASA TRACERS mission is designed for this purpose. I will present a TRACERS-THEMIS conjunction near the peak of a geomagnetic storm after the IMF had turned northward. In the low-altitude cusp, TRACERS observed signatures consistent with lobe reconnection poleward of the cusp, including reversed ion dispersions and sunward convection. Concurrent THEMIS observations at the low-latitude magnetopause reveal the presence of a magnetosheath boundary layer (MSBL) and capture of magnetosheath plasma on magnetospheric field lines, both consistent with poleward-of-cusp reconnection. Global simulations of the event show that poleward-of-cusp reconnection was adding magnetic fields and plasma to the magnetosphere, and in the process moving the cusp poleward. The event also illustrates how the magnetosphere and cusp recover when the IMF turns northward after a storm has eroded the magnetopause inward and moved the cusp equatorward.

Jupiter’s moon Europa is a key target in the search for extraterrestrial life, but assessing its habitability via magnetic induction requires a well-grounded understanding of the plasma environment. At Europa, this task relies on magnetohydrodynamic (MHD) models that have been developed over many years. While powerful, these models are computationally expensive, with some codes requiring > 12 hours on a 2,000-core machine. Fitting spacecraft observations to MHD models demands many runs, resulting in a potentially days- or weeks-long process. This presents a major bottleneck for missions such as Europa Clipper and JUICE, potentially limiting their scientific return.
In this talk, I introduce a transformer-based surrogate for a state-of-the-art MHD model used to help characterize Europa’s subsurface ocean. The surrogate evaluates in milliseconds on a laptop rather than hours on a supercomputer, achieving a speed-up of approximately 40,000x while delivering high-fidelity, uncertainty-aware magnetic field predictions. This acceleration enables three new scientific pathways that are feasible with MHD alone: large-scale parameter surveys, simulation-based inference, and feature-importance analysis. These analyses are important as the environment is poorly constrained observationally. Overall, this approach represents a paradigm shift in the investigation of space plasmas and opens the door to a host of novel science investigations.

NASA science missions are often complex systems of systems, involving various stakeholders, including the United States’ Congress. To ensure a clear and concise communication of expectations, requirements, and constraints, NASA has adopted the Science Traceability Matrix (STM). STM provides a logical flow from the decadal survey to science goals and objectives, mission and instrument requirements, and data products. STM serves as a summary of what science will be achieved and how it will be achieved, with a clear definition of what mission success will look like. In this seminar, I will present the STM from the Parker Solar Probe (PSP), including requirements relating to the plasma instrument for which I am a co-investigator. I will describe how our team used the STM to map the mission’s top-level requirements to mission success criteria and helped to eliminate any single point of failure that could end the mission prematurely. I will then present my own research on magnetic switchbacks in the PSP magnetic and plasma observations and their role in solar wind acceleration and heating. I will conclude the seminar by discussing how my research on the temporal evolution of switchbacks in the solar wind led to a new STM, and helped to chart a multidisciplinary path to designing a ground-breaking science mission concept, titled Space Weather Investigation Frontier (SWIFT), with the potential to improve space weather forecasting lead times by up to 40%.

Extraterrestrial EM induction was first carried out in the 1970s
by forming magnetic transfer functions for the Moon as the ratio of
magnetic fields observed at the surface (Apollo 12) to those observed in
distant orbit (Explorer 35). In March 2025, a similar analysis was
performed using the Lunar Magnetotelluric Sounder (LMS) on Blue Ghost
Mission 1 and the ARTEMIS spacecraft. In spite of nearly 90 deg arc
distance between these surface locations, the derived subsurface
conductivities are very similar. This sharply limits contemporary
temperatures under the western nearside of the Moon in spite of its past
history of widespread volcanism. The two-week surface mission recorded
surface electric and magnetic fields in the solar wind, magnetosheath, and
magnetotail, including an eclipse and sunset. Plasma properties correlate
well with ARTEMIS.

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From the solar wind to more distant astrophysical plasmas, magnetohydrodynamic (MHD) turbulence is ubiquitous in our universe. Interactions between Alfvénic modes within these turbulent systems transfer energy from large to small spatial scales, but the relationship between the turbulence and the underlying Alfvénic fluctuations remains an active subject of research. In this seminar, I will first review the physics of nonlinear Alfvénic interactions in a simple incompressible MHD model and then discuss an important feature of MHD turbulence that is not consistent with linear Alfvén waves: excess energy in magnetic fluctuations compared to velocity fluctuations. The presence of this “residual energy” suggests a key role for nonlinear modes that do not satisfy the Alfvén wave dispersion relation but still retain some Alfvénic properties. We generate these Alfvénic quasimodes via the nonlinear interaction of counter-propagating Alfvén waves in a laboratory experiment, and our measurements demonstrate that the observed quasimodes can contain either excess magnetic or excess kinetic energy [Abler, et. al, in prep]. We show theoretically that net excess magnetic energy, as observed in the solar wind, can arise over many nonlinear interactions as a consequence of initial and boundary conditions [Dorfman, et. al. ApJ 2025]. The need to produce more astrophysicaly relevant conditions in the laboratory to open a new area of research for future turbulence studies will also be discussed [Dorfman, et. al. JPP 2025].

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Galileo, Cassini and Juno space missions have provided much data on gas giant magnetospheres. Here we examine the important commonalities of the two systems that also characterise the differences to the plasma environment of the inner planets. Both systems are fast rotators and have internal sources of magnetospheric material deep within the system. The internal sources means there must be a system for transport of material outward. Commonly, marginally stable interchange motions of flux tubes are invoked to provide diffusion on relatively small scales transverse to the field. This no doubt occurs near the source but processes like self-organisation may lead to more ordered motion at larger distances. A large distinction between Jupiter and Saturn systems is that the jovian planetary magnetic field is far from axially symmetric with respect to the planetary rotation axis whereas Saturn’s field is close to axially symmetric. However, despite this, the Saturn system does exhibit variable periodicities in plasma, radio, aurora and the external magnetic field around 10.7 hours. The external magnetic source was a surprise; the ubiquitous Saturn oscillations are still described as “mysterious”. No similar oscillations are recorded at Jupiter. We shall aim to remove some of the mystery and suggest that the dynamical effect of rotation has not been fully appreciated in either system.

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