arXiv subjects

Zilong Peng

Publications and source records attributed to Zilong Peng.

3 recordsLinked to original sources

arXiv2026

Particle-resolved pathways to energetic-ion formation in a fluctuating low-current hollow-cathode plume

Energetic-ion formation in a low-current hollow-cathode plume is investigated using experiments, self-consistent electrostatic particle-in-cell (PIC) simulation, and particle-resolved analysis. Retarding potential analyzer measurements show a substantial energetic-ion population over discharge currents of 0.8-3.5 A, while probe measurements reveal broadband plume fluctuations. Two-point phase-derived frequency-wavenumber measurements do not resolve a continuous ion-acoustic dispersion branch within the principal apparent-wavenumber interval. Because the inferred wavenumber is obtained from a cross-spectral phase defined modulo 2pi, the fluctuation diagnostics do not provide an unambiguous modal attribution for the energetic-ion population. A representative PIC plume, used as a qualitative kinetic reference, likewise develops broadband time-dependent electrostatic fluctuations together with a nonthermal energetic-ion population. Particle-resolved analysis shows that the energetic outflow is dominated by ions generated through ionization inside the plume, while source localization biases access to distinct trajectory and escape families. Matched field controls further show that time-averaged and frozen fields strongly suppress access to high-energy trajectories relative to the full time-dependent field over the analyzed interval. At the single-particle level, ion kinetic-energy gain is determined by electrostatic-field work accumulated along the actual trajectory, with different escape families exhibiting distinct radial and axial work contributions. These results establish a source-trajectory-field-work pathway for energetic-ion formation that can be identified without first assigning the fluctuating plume to a unique resolved plasma mode.

physics.plasm-ph↗

arXiv2026

AlgoPlasma: Open Algorithms for Plasma Modeling

AlgoPlasma is an open-source library in which core numerical algorithms for plasma modeling are implemented as modular, well-documented, and independently testable components. Rather than offering a complete simulation code, it allows researchers to select, adapt, and assemble the required components into application-specific workflows. The current release is centered on particle-based simulation, while AlgoPlasma is designed to encompass a broader range of approaches to plasma modeling. It provides components for particle initialization and advancement, particle--grid coupling, field solution, collision modeling, parallel data exchange, input/output, and selected fluid updates. Documentation links mathematical formulations to source implementations, interfaces, and usage, while verification and validation cases evaluate numerical accuracy and physical behavior. AlgoPlasma thus establishes a shared algorithmic foundation for plasma modeling, transforming repeatedly reimplemented numerical methods into open, reusable, tested, and explainable components for research, verification, education, and collaborative development.

physics.plasm-ph↗

arXiv2026

Likelihood topology and applicability limits of spatial anti-aliasing inversion for folded electron drift instability dispersion in Hall thrusters

The electron drift instability (EDI) is widely recognized as the leading mechanism for anomalous electron transport in Hall thrusters, but its millimeter and sub-millimeter wavelength makes conventional wave-probe analysis strongly limited by spatial aliasing. A multi-geometry spatial anti-aliasing algorithm provides a route for wave-probe diagnostics to break the spatial Nyquist limit, but its effectiveness for nonmonotonic, folded, multi-resonance EDI dispersion has not been quantified. Using the numerically solved linear kinetic EDI dispersion relation under typical Hall-thruster discharge parameters as a benchmark, this work evaluates two-dimensional maximum-likelihood spatial anti-aliasing inversion based on two-probe synthetic signals generated for 25 simulated angle-spacing configurations. For a sampling frequency fs = 100 MHz and signal-to-noise ratio SNR = 10, the method breaks the conventional Nyquist wavenumber limit of about 1 krad/m, extends the accessible range to about 22 krad/m, and recovers the dominant likelihood ridges associated with the first- to fifth-order EDI branches. Parameter scans further show that the statistical realization count L mainly determines the suppression of spurious alias peaks, whereas the frequency resolution delta f mainly determines local branch separation near folded extrema. These results provide benchmark sampling and segmentation constraints for multi-geometry wave-probe diagnosis of EDI dispersion under the present synthetic conditions and can guide future experiments.

physics.plasm-ph↗