Kristopher Klein

About

Kristopher Klein is a faculty member associated with the Program in Applied Mathematics at the University of Arizona. His research interests include Solar and Heliospheric Research, Theoretical Astrophysics, and related fields. He is involved in the study of planetary science, astrophysics, and energy systems, with a particular focus on topics relevant to space and planetary environments. His professional profile indicates active engagement in research related to the Parker Solar Probe and other astrophysical phenomena, contributing to the understanding of solar and planetary processes.

Research topics

• Meteorology
• Physics
• Atmospheric sciences
• Astrophysics
• Computational physics
• Environmental science
• Astronomy
• Astrobiology

Selected publications

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum

  Space Science Reviews · 2023 · 147 citations

  Abstract Launched on 12 Aug. 2018, NASA’s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission’s primary science goal is to determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expect…

  PublisherOA PDFDOI

• The near-Sun streamer belt solar wind: turbulence and solar wind acceleration

  Astronomy and Astrophysics · 2021 · 41 citations

  The fourth orbit of Parker Solar Probe (PSP) reached heliocentric distances down to 27.9 R ⊙ , allowing solar wind turbulence and acceleration mechanisms to be studied in situ closer to the Sun than previously possible. The turbulence properties were found to be significantly different in the inbound and outbound portions of PSP’s fourth solar encounter, which was likely due to the proximity to the heliospheric current sheet (HCS) in the outbound period. Near the HCS, in the streamer belt wind,…

  PublisherOA PDFDOI

• Multispacecraft Measurements of the Evolving Geometry of the Solar Alfvén Surface over Half a Solar Cycle

  The Astrophysical Journal Letters · 2025-12-11 · 6 citations

  articleOpen accessCorresponding

  Abstract The geometry of a star’s Alfvén surface determines stellar angular momentum loss, separates a causally distinct “corona” and stellar wind, and potentially affects exoplanetary habitability. The solar Alfvén surface is the only such structure that is directly measurable and, since 2021, has been routinely measured in situ by NASA’s Parker Solar Probe (Parker). We use these unique measurements in concert with Solar Orbiter and L1 in situ data spanning the first half of solar cycle 25 in t…

  PublisherDOI

• The dielectric response of plasmas with arbitrary gyrotropic velocity distributions

  Physics of Plasmas · 2025-09-01 · 4 citations

  articleOpen access1st authorCorresponding

  Hot and tenuous plasmas are frequently far from local thermodynamic equilibrium, necessitating sophisticated methods for determining the associated plasma dielectric tensor and normal mode response. The Arbitrary Linear Plasma Solver is a numerical tool for calculating such responses of plasmas with arbitrary gyrotropic background velocity distribution functions (VDFs). To model weakly and moderately damped plasma waves accurately, we have updated the code to use an improved analytic continuatio…

  PublisherOA PDFDOI

• Impact of Two-population <i>α</i>-particle Distributions on Plasma Stability

  The Astrophysical Journal Letters · 2025-07-17 · 3 citations

  articleOpen access

  Abstract The stability of weakly collisional plasmas is well represented by linear theory, and the generated waves play an essential role in the thermodynamics of these systems. The velocity distribution functions (VDFs) characterizing kinetic particle behavior are commonly represented as a sum of anisotropic bi-Maxwellians. A three bi-Maxwellian model is commonly applied for the ions, assuming that the VDF consists of a proton core, a proton beam, and a single He ( α ) particle population, each…

  PublisherDOI

Recent grants

• AGS-PRF: Understanding the Nature of Turbulent Fluctuations in the Near Sun Solar Wind

  NSF · $172k · 2014–2016

Frequent coauthors

• J. C. Kasper

  167 shared

• S. D. Bale

  161 shared

• Mihailo M. Martinović

  151 shared

• M. L. Stevens

  114 shared

• Thierry Dudok de Wit

  International Space Science Institute

  89 shared

• B. Lavraud

  Centre National de la Recherche Scientifique

  88 shared

• A. W. Case

  Center for Astrophysics Harvard & Smithsonian

  86 shared

• G. G. Howes

  85 shared

Education

• PhD, Physics and Astronomy

  University of Iowa

  2013

Similar researchers at University of Arizona

• Kevin Linh-86
• Joanna Maselh-35
• Laura Condonh-35