Fully-implicit Particle-in-Cell model of a Magnetic Nozzle with electromagnetic power deposition
Abstract
A fraction of the electromagnetic power used to generate and heat the plasma in helicon sources and electrodeless plasma thrusters can leak into the outer expansion region, interacting with the plasma in the magnetic nozzle and affecting the performance of the device. This work analyzes the properties of the plasma in a convergent-divergent magnetic nozzle when right-hand polarized waves of varying amplitude propagate into it. This is accomplished with a 1D3V fully-implicit, Vlasov-Darwin particle-in-cell model of the collisionless ion and electron plasma in a magnetic tube. The code exactly conserves charge locally and energy globally. It features a nonuniform grid and an enhanced substepping routine for the macroparticle trajectories. The requirement that the expansion be current-free is satisfied thanks to linear closed-loop controllers on the injection and downstream boundary conditions. Wave heating increases the electron perpendicular temperature, especially in the vicinity of an electron cyclotron resonance surface, always present inside the magnetic nozzle of a helicon device. The energized electrons become anisotropic, and drive a more pronounced potential drop and a higher ion acceleration than in the absence of waves, at the expense of the wave power. The computed moments of the ion and electron distributions reveal the dominant balance of the electron thermal terms, electrostatic terms, and ion inertial terms in the momentum and energy equations. Wave heating helps populate otherwise-inaccessible regions of the electron phase space and modifies the doubly-trapped electron population found in the purely electrostatic case. The overall efficiency of the magnetic nozzle increases mildly at low wave power, but drops quickly as it is increased beyond a threshold, as part of the energy is wasted...
Related
- A semi-implicit unified gas-kinetic wave-particle method with energy-conserving electromagnetic coupling for multiscale plasmas
- Analysis of collisional and facility effects in a magnetic nozzle plasma expansion
- A fully implicit electromagnetic energy- and charge-conserving PIC model for simulations of high-β plasma
- An implicit multiscale solver for steady kinetic equations based on wave-particle decomposition
- A physics-based-preconditioned quasi-Newton solver for energy- and momentum-conserving implicit hybrid particle-in-cell simulations
BibTeX
@misc{merino2026fullyimplicit,
title = {{Fully-implicit Particle-in-Cell model of a Magnetic Nozzle with electromagnetic power deposition}},
author = {Mario Merino and Juan Martín-Hernández and Pedro Jiménez-Jiménez and Luis Chacón},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.09771},
eprint = {2606.09771},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.09771},
}
RIS
TY - UNPB
TI - Fully-implicit Particle-in-Cell model of a Magnetic Nozzle with electromagnetic power deposition
AU - Mario Merino
AU - Juan Martín-Hernández
AU - Pedro Jiménez-Jiménez
AU - Luis Chacón
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2606.09771
UR - https://arxiv.org/abs/2606.09771
AB - A fraction of the electromagnetic power used to generate and heat the plasma in helicon sources and electrodeless plasma thrusters can leak into the outer expansion region, interacting with the plasma in the magnetic nozzle and affecting the performance of the device. This work analyzes the properties of the plasma in a convergent-divergent magnetic nozzle when right-hand polarized waves of varying amplitude propagate into it. This is accomplished with a 1D3V fully-implicit, Vlasov-Darwin particle-in-cell model of the collisionless ion and electron plasma in a magnetic tube. The code exactly conserves charge locally and energy globally. It features a nonuniform grid and an enhanced substepping routine for the macroparticle trajectories. The requirement that the expansion be current-free is satisfied thanks to linear closed-loop controllers on the injection and downstream boundary conditions. Wave heating increases the electron perpendicular temperature, especially in the vicinity of an electron cyclotron resonance surface, always present inside the magnetic nozzle of a helicon device. The energized electrons become anisotropic, and drive a more pronounced potential drop and a higher ion acceleration than in the absence of waves, at the expense of the wave power. The computed moments of the ion and electron distributions reveal the dominant balance of the electron thermal terms, electrostatic terms, and ion inertial terms in the momentum and energy equations. Wave heating helps populate otherwise-inaccessible regions of the electron phase space and modifies the doubly-trapped electron population found in the purely electrostatic case. The overall efficiency of the magnetic nozzle increases mildly at low wave power, but drops quickly as it is increased beyond a threshold, as part of the energy is wasted...
ER -