Space Physics at Princeton

Welcome to Space Physics at Princeton

The Space Physics group in the Department of Astrophysical Sciences:

  • Educates Princeton University undergraduate and graduate students through hands-on work in an active space instrument laboratory and with scientific data from space
  • Conceives, designs develops, calibrates, and flies cutting-edge space instrumentation on NASA missions
  • Analyzes space data from the Sun and Solar Corona through to the Solar Wind and terrestrial and planetary magnetospheres, including the global heliosphere and its interaction with the local interstellar medium
  • Discovers scientific secrets of our space environs through integrated observations, data analysis, and theoretical understanding

We are the lead institution for numerous NASA Heliophysics missions and instruments that Prof. David J. McComas serves as the principal investigator for:

Interstellar Mapping and Acceleration Probe (IMAP) mission – under development and launching in 2025 to explore the details of particle acceleration and the Sun’s interaction with the local interstellar medium;

Parker Solar Probe (PSP), Integrated Science investigation of the Sun (ISʘIS) instrument suite – launched 8/12/2018 to measure energetic particles as close in as nine solar radii from the Sun’s surface;

Interstellar Boundary Explorer (IBEX) mission – launched in 2008 and still exploring the boundaries of our heliosphere and its interaction with the local interstellar medium;

New Horizons, Solar Wind Around Pluto (SWAP) instrument – launched in 2006, measured the plasma environments of Pluto and the Jovian magnetosphere and continues to make unprecedented observations of interstellar pickup ions;

Advanced Composition Explorer (ACE), Solar Wind Electron Proton Alpha Monitor (SWEPAM) instrument – launched in 1997 and still providing solar wind data from the Sun-Earth Lagrangian point (L1);

Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission – returned the first stereo imaging of the Earth’s dynamic magnetosphere (operational from 2008-2017);

Ulysses, Solar Wind Observations Over the Poles of the Sun (SWOOPS) instrument – discovered the three-dimensional structure of the solar wind from the first and only mission to fly over the poles of the Sun (operational from 1990 - 2009).



Sun & Princeton Shield

Research News

Unified Picture of the Local Interstellar Magnetic Field from Voyager and IBEX
April 26, 2023

Prior to the Voyagers’ heliopause crossings, models and the community expected the magnetic field to show major rotations across the boundary. Surprisingly, the field showed no significant change in direction from the heliospheric Parker Spiral at either Voyager location. Meanwhile, a major result from the IBEX mission is the derived magnitude…

Publication: Variability of Antenna Signals From Dust Impacts
March 30, 2023

Electric field instruments carried by spacecraft (SC) are complementary to dedicated dust detectors by registering transient voltage perturbations caused by impact-generated plasma. The signal waveform contains information about the interaction between the impact-generated plasma cloud and the elements of SC-antenna system. The variability of…

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…