News

Publication: Taylor Microscale and Effective Reynolds Number near the Sun from PSP
July 2, 2022

The Taylor microscale is a fundamental length scale in turbulent fluids, representing the end of fluid properties and onset of dissipative processes. The Taylor microscale can also be used to evaluate the Reynolds number in classical turbulence theory. Although the solar wind is weakly collisional, it approximately behaves as a…

Professor David J. McComas receives the 2022 EGU Hannes Alfvén Medal
June 3, 2022

Congratulations to Princeton University Professor David McComas, he received, Hannes Alfvén Medal at the 2022 EGU General Assembly in Austria.

The European Geosciences Union (EGU) awarded 50 recipients at this year’s General Assembly, with Union Medals and Awards, Division Medals, and Division Outstanding Early Career Scientist Awards…

Space Physics Students Graduate as class of 2022
May 23, 2022

Congratulations to Sydney Evans, Grace Gong, and Nina Arcot as they successfully graduate as part of the class of 2022.

They have successfully completed a number of different projects with the group, and we would like to thank them for their dedication and for the important contributions that they have made.

To find out more…

Publication: In Situ Observations of Interstellar Pickup Ions from 1 au to the Outer Heliosphere
May 9, 2022

Interstellar pickup ions are an ubiquitous and thermodynamically important component of the solar wind plasma in the heliosphere. These PUIs are born from the ionization of the interstellar neutral gas, consisting of hydrogen, helium, and trace amounts of heavier elements, in the solar wind as the heliosphere moves through the local…

Publication: Water-Group Pickup Ions From Europa-Genic Neutrals Orbiting Jupiter
May 4, 2022

Water-group gas continuously escapes from Jupiter's icy moons to form co-orbiting populations of particles or neutral toroidal clouds. These clouds provide insights into their source moons as they reveal loss processes and compositions of their parent bodies, alter local plasma composition, and act as sources and sinks for magnetospheric…

Publication: Closed Fluxtubes and Dispersive Proton Conics at Jupiter's Polar Cap
May 3, 2022

Two distinct proton populations are observed over Jupiter's southern polar cap: a ~1 keV core population and ~1-300 keV dispersive conic population at 6–7 RJ planetocentric distance. We find the 1 keV core protons are likely the seed population for the higher-energy dispersive conics, which are accelerated from
a distance of ∼3-5 RJ…

Publication: Sub-Alfvénic Solar Wind Observed by the Parker Solar Probe: Characterization of Turbulence, Anisotropy, Intermittency, and Switchback
Feb. 11, 2022

In the lower solar coronal regions where the magnetic field is dominant, the Alfvén speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super-Alfvénic, i.e., the wind speed greatly exceeds the Alfvén speed. The transition between these regimes is classically described as the "Alfvén point" but may in…

Publication: Clouds of Spacecraft Debris Liberated by Hypervelocity Dust Impacts on Parker Solar Probe
Jan. 24, 2022

Hypervelocity impacts on spacecraft surfaces produce a wide range of effects including transient plasma clouds, surface material ablation, and for some impacts, the liberation of spacecraft material as debris clouds. This study examines debris-producing impacts on the Parker Solar Probe spacecraft as it traverses the densest part of the…

Publication: Anomalous Cosmic-Ray Oxygen Observations into 0.1 au
Jan. 21, 2022

The Integrated Science Investigation of the Sun instrument suite onboard NASA's Parker Solar Probe mission continues to measure solar energetic particles and cosmic rays closer to the Sun than ever before. Here, we present the first observations of cosmic rays into 0.1 au (21.5 solar radii), focusing specifically on oxygen from ∼2018.7 to ∼2021…

Publication: Geometry of Magnetic Fluctuations near the Sun from the Parker Solar Probe
Dec. 22, 2021

Solar wind magnetic fluctuations exhibit anisotropy due to the presence of a mean magnetic field in the form of the Parker spiral. Close to the Sun, direct measurements were not available until the recently launched Parker Solar Probe (PSP) mission. The nature of the anisotropy and geometry of the magnetic fluctuations play a fundamental role…