Publication: Compensating for gyroradius effects in beamlines with small Helmholtz coils
March 16, 2023

Measurements of lighter, low-energy charged particles in a laboratory beamline are complicated due to the influence of Earth’s magnetic field. Rather than nulling out the Earth’s magnetic field over the entire facility, we present a new way to correct particle trajectories using much more spatially limited Helmholtz coils. This approach is…

Soaking up the Sun - NASA funded lab sets its sights on the heliosphere
March 7, 2023

NASA-Funded lab sets its sights on the heliosphere.

The full article can be found here.

NASA Outreach: "The Heliosphere Has Ripples!"
Feb. 24, 2023

A recent study led by Dr. Zirnstein showed that the heliosphere boundaries are rippled. See the links below to a NASA social media video:

InstragramFacebook, and…

Publication: Tracking the Rapid Opening and Closing of Polar Coronal Holes through IBEX ENA Observations
Jan. 25, 2023

Fast solar wind (SW) flows outward from polar coronal holes (PCHs). The latitudinal extent of the fast SW varies during different phases of the solar cycle. The fast SW in the inner heliosheath produces a flatter proton spectrum than the slow SW that can be observed through energetic neutral atoms (ENAs) by the Interstellar Boundary Explorer …

David J. McComas Will Receive the 2023 Arctowski Medal
Jan. 23, 2023

McComas has made seminal contributions through innovative mission and instrumentation development that have benefited and supported the entire scientific community and led ground-breaking observations, analysis, and discovery of fundamental physics of the heliosphere and the very local interstellar medium, the solar wind, and the Earth’s and…

Publication: Physical Correlations Lead to Kappa Distributions
Nov. 23, 2022

The recently developed concept of "entropic defect" is important for understanding the foundations of thermodynamics in space plasma physics, and more generally for systems with physical correlations among their particles. Using this concept, this paper derives the basic formulation of the distribution function of velocities (or kinetic…

Publication: Thermodynamics of the Inner Heliosheath
Oct. 13, 2022

We derive annual sky maps of the proton temperature in the inner heliosheath (IHS), and track their temporal evolution over the years 2009–2016 of Interstellar Boundary Explorer observations. Other associated thermodynamic parameters also determined are the density, kappa (the parameter that characterizes kappa distributions), temperature rate,…

Publication: Oblique and rippled heliosphere structures from the Interstellar Boundary Explorer
Oct. 12, 2022

Past analysis has shown that the heliosphere structure can be deduced from correlations between long-scale solar wind pressure evolution and energetic neutral atom emissions. However, this required spatial and temporal averaging that smoothed out small or dynamic features of the heliosphere. In late 2014, the solar wind dynamic pressure…

Publication: Explanation of Heliospheric Energetic Neutral Atom Fluxes Observed by the Interstellar Boundary Explorer
Oct. 4, 2022

Interstellar neutral atoms propagating into the heliosphere experience charge exchange with the supersonic solar wind (SW) plasma, generating ions that are picked up by the SW. These pickup ions (PUIs) constitute ~25% of the proton number density by the time they reach the heliospheric termination shock (HTS). Preferential acceleration of PUIs…

Publication: Beta-Dependent Constraints on Ion Temperature Anisotropy in Jupiter's Magnetosheath
Aug. 5, 2022

Most space plasmas are weakly collisional. Due to the low collision rate, the plasmas are routinely out of local thermal equilibrium and often exhibit non-Maxwellian velocity distributions. The charged particles typically exhibit anisotropy in temperature measurements, that is, distinct temperatures are observed perpendicular and parallel (