424 citations · 2.6k across the 108 of their papers we have counts for
32 papers · 1 filter
Wave Emission and Absorption in a Near-Sun Proton-Cyclotron Wave Storm
Kristopher G Klein, Daniel Verscharen, Mihailo Martinovic +5
Quantification of energy transport and dissipation in weakly collisional heliospheric plasmas that are far from local thermodynamic equilibrium is an outstanding scientific problem…
Decomposition of Solar Wind Velocity Distribution Functions with Orthogonal Polynomials
Byeongseon Park, Primoz Kajdic, Daniel Verscharen +7
We present a framework for decomposing solar-wind velocity distribution functions (VDFs) using orthogonal polynomial bases. We aim to establish a practical procedure for applying p…
Collisionless stationary states of a stratified plasma in an expanding magnetic tube with stochastic heating
Luca Barbieri, Pascal Démoulin, Daniel Verscharen
We investigate the collisionless kinetic structure of the upper solar atmosphere in an expanding magnetic field. Building on established velocity-filtration models, we extend the s…
Parker Solar Probe Observations of Preferential Heating of Protons over Alpha Particles near Turbulent Coherent Structures
Jiayang Xi, Tieyan Wang, Daniel Verscharen +15
Solar wind alpha particles exhibit preferential heating and acceleration relative to protons; however, their behavior in the vicinity of turbulent coherent structures remains less…
The Damping and Instability of Ion-acoustic Waves in the Solar Wind: Solar Orbiter Observations
Hao Ran, Daniel Verscharen, Jesse Coburn +6
Observations of solar wind velocity distribution functions (VDFs) commonly reveal fine-scale structures. These features strongly influence kinetic processes such as wave damping an…
A Non-Spherical Model for the Solar Coronal Magnetic Field
Ziqi Wu, Jiansen He, Chuanpeng Hou +7
The coronal magnetic field plays a fundamental role in governing coronal activities, driving space-weather events, and shaping the heliosphere. Due to a lack of direct observations…
Alfvénic solar wind intervals observed by Solar Orbiter: Exploiting the capability of the SWA plasma suite and source region investigation
R. D'Amicis, J. M. Raines, S. Benella +32
Fast and slow solar wind have distinct properties linked to their solar sources.Alfvénic slow wind complicates the usual speed-based classification, especially at intermediate spee…
How the Oblique Drift Instability Alters Solar Wind Heating and Constrains the Distribution of Solar Wind Observations
Mihailo M. Martinovic, Kristopher G. Klein, Leon Ofman +6
Ion-driven plasma instability thresholds, derived from linear theory, constrain the distribution of solar observations in parameter space, defining boundaries of stable plasma para…
Double Power-law Electron Spectra in Solar Flares Due to Temperature Anisotropy Instabilities
Martín Astete, Mario Riquelme, Daniel Verscharen
Despite extensive observational and theoretical efforts, the physical processes responsible for shaping the diversity of accelerated electron spectra observed in solar flares remai…
Observational Constraints on the Radial Evolution of O Temperature and Differential Flow in the Inner Heliosphere
Yeimy J. Rivera, Kristopher G. Klein, Joseph H. Wang +15
Over decades of solar wind observations, heavy ions have been observed to have a higher temperature and flow faster than protons in the solar corona and heliosphere. Remote observa…
Quasi-parallel anti-sunward propagating whistler waves associated to the electron-deficit in the near-Sun solar wind: Particle-in-Cell simulation
Alfredo Micera, Daniel Verscharen, Jesse T. Coburn +1
In-situ observations of the solar wind have shown that the electron velocity distribution function (VDF) consists of a quasi-Maxwellian core, comprising most of the electron popula…
Impact of Two-Population -particle Distributions on Plasma Stability
Mihailo M. Martinović, Kristopher G. Klein, Rossana De Marco +3
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 velocit…
Solar Electron Beam -- Langmuir Wave Interactions and How They Modify Solar Electron Beam Spectra: Solar Orbiter Observations of a Match Made in the Heliosphere
Camille Y. Lorfing, Hamish A. S. Reid, Raul Gomez-Herrero +7
Solar Orbiter's four in-situ instruments have recorded numerous energetic electron events at heliocentric distances between 0.5 and 1au. We analyse energetic electron fluxes, spect…
The Effects of Non-Equilibrium Velocity Distributions on Alfvén Ion-Cyclotron Waves in the Solar Wind
Jada Walters, Kristopher G. Klein, Emily Lichko +3
In this work, we investigate how the complex structure found in solar wind proton velocity distribution functions (VDFs), rather than the commonly assumed two-component bi-Maxwelli…
The effect of variations in magnetic field direction from turbulence on kinetic-scale instabilities
Simon Opie, Daniel Verscharen, Christopher H. K. Chen +2
At kinetic scales in the solar wind, instabilities transfer energy from particles to fluctuations in the electromagnetic fields while restoring plasma conditions towards thermodyna…
Does Turbulence along the Coronal Current Sheet Drive Ion Cyclotron Waves?
Daniele Telloni, Gary P. Zank, Laxman Adhikari +32
Evidence for the presence of ion cyclotron waves, driven by turbulence, at the boundaries of the current sheet is reported in this paper. By exploiting the full potential of the jo…
Thermal energy budget of electrons in the inner heliosphere: Parker Solar Probe Observations
Joel B. Abraham, Daniel Verscharen, Robert T. Wicks +4
We present an observational analysis of the electron thermal energy budget using data from Parker Solar Probe. We use the macroscopic moments, obtained from our fits to the measure…
Radial evolution of thermal and suprathermal electron populations in the slow solar wind from 0.13 to 0.5 au : Parker Solar Probe Observations
Joel B. Abraham, Christopher J Owen, Daniel Verscharen +8
We develop and apply a bespoke fitting routine to a large volume of solar wind electron distribution data measured by Parker Solar Probe (PSP) over its first five orbits, covering…
The Stability of the Electron Strahl against the Oblique Fast-magnetosonic/Whistler Instability in the Inner Heliosphere
Seong-Yeop Jeong, Joel B. Abraham, Daniel Verscharen +8
We analyze the micro-kinetic stability of the electron strahl in the solar wind depending on heliocentric distance. The oblique fast-magnetosonic/whistler (FM/W) instability has em…
Test Problems for Potential Field Source Surface Extrapolations of Solar and Stellar Magnetic Fields
David Stansby, Daniel Verscharen
The potential field source surface (PFSS) equations are commonly used to model the coronal magnetic field of the Sun and other stars. As with any computational model, solving equat…
Exploring the Solar Wind from its Source on the Corona into the Inner Heliosphere during the First Solar Orbiter - Parker Solar Probe Quadrature
Daniele Telloni, Vincenzo Andretta, Ester Antonucci +68
This Letter addresses the first Solar Orbiter (SO) -- Parker Solar Probe (PSP) quadrature, occurring on January 18, 2021, to investigate the evolution of solar wind from the extend…
Strong perpendicular velocity-space in proton beams observed by Parker Solar Probe
J. L. Verniero, B. D. G. Chandran, D. E. Larson +16
The SWEAP instrument suite on Parker Solar Probe (PSP) has detected numerous proton beams associated with coherent, circularly polarized, ion-scale waves observed by PSP's FIELDS i…
Growth of Outward Propagating Fast-Magnetosonic/Whistler Waves in the Inner Heliosphere Observed by Parker Solar Probe
Jiansen He, Ying Wang, Xingyu Zhu +3
The solar wind in the inner heliosphere has been observed by Parker Solar Probe (PSP) to exhibit abundant wave activities. The cyclotron wave modes in the sense of ions or electron…
Deriving the bulk properties of solar wind electrons observed by Solar Orbiter: A preliminary study of electron plasma thermodynamics
Georgios Nicolaou, Robert T. Wicks, Christopher J. Owen +8
We demonstrate the calculation of solar wind electron bulk parameters from recent observations by Solar Wind Analyser Electron Analyser System on board Solar Orbiter. We use our me…