About

Bernard Parent is an Associate Professor of Aerospace and Mechanical Engineering at the University of Arizona and a member of the Graduate Faculty. He obtained his BS in Mechanical Engineering from McGill University in 1996 and his PhD in Aerospace Science and Engineering from the University of Toronto Institute for Aerospace Studies in 2002. During his PhD, he developed a CFD code to simulate chemically-reacting turbulent flows in scramjets. His research has focused on extending his CFD code to handle plasma effects, and he has worked at institutions including Princeton University, the Tokyo Institute of Technology, and Pusan National University before joining the University of Arizona in August 2019. His active research areas include simulating plasma flow control, plasma-assisted combustion, and re-entry flows.

Research topics

• Mechanics
• Physics
• Chemistry
• Engineering
• Aerospace engineering
• Atomic physics

Selected publications

• Electron density depletion in reentry plasma flows using pulsed electric fields

  Physics of Fluids · 2026-03-01

  articleOpen accessSenior author

  Communication blackout due to the plasma layer creates a critical telemetry gap for reentry vehicles. To mitigate this, we present the first fully coupled simulation of high-voltage pulsed discharges interacting with a Mach 24 flowfield using an advanced numerical framework. The results demonstrate that the applied electric field generates a large, non-neutral plasma sheath near the cathode, depleting electron density by several orders of magnitude over a distance commensurate with the height of the shock layer. This depletion window effectively reduces the attenuation of a 4 GHz signal from 60% to 4% with a manageable power requirement of 66 W/cm2 of exposed cathode surface. Feasibility analysis indicates that this system can be powered by a battery pack weighing less than 3 kg for a typical reentry trajectory, with further mass reductions possible through intermittent transmission. A sensitivity analysis reveals that the sheath topology is governed principally by ion kinetics; specifically, corrections to ion mobility at high reduced electric fields lead to enhanced space-charge shielding and a subsequent contraction of the sheath. Conversely, the sheath structure is largely insensitive to the electron mobility model. Finally, we argue that the present drift-diffusion model likely yields a conservative lower bound for mitigation performance. A kinetic approach accounting for ballistic ion transport and non-local ionization would likely predict thicker sheaths and lower attenuation for equivalent power deposition.

  PublisherOA PDFDOI

• Superelastic Heating in Treanor-Gordiets Plasmas: A Unified Analytic Closure

  ArXiv.org · 2026-01-28

  articleOpen access1st authorCorresponding

  In thermally non-equilibrium plasmas, conventional harmonic models can significantly mispredict superelastic electron heating rates. When the vibrational temperature exceeds the gas temperature ($T_{\rm v}>T_{\rm g}$), these models underestimate energy transfer by several times; conversely, they overestimate heating when $T_{\rm g}>T_{\rm v}$. We show that this discrepancy arises from neglecting the exponential heating from overpopulated, high-lying states in anharmonic Treanor-Gordiets distributions, and their thermodynamic depopulation at high gas temperatures. To resolve this, we derive a closed-form, thermodynamically consistent macroscopic closure based on detailed balance and a second-order Dunham expansion. This unified framework introduces an analytic anharmonic correction factor that captures the kinetic competition between vibrational-vibrational (V-V) up-pumping and vibrational-translational (V-T) relaxation. By predicting the Treanor minimum, this formulation recovers the fidelity of full state-to-state kinetic benchmarks. Ultimately, this model provides a governing equation for heat exchange between electrons and excited states in non-equilibrium environments -- including plasma-assisted combustion and hypersonic flows -- enabling the development of accurate, rate-limited reduced-order models for macroscopic fluid solvers.

  PublisherOA PDF

• Superelastic Heating in Treanor-Gordiets Plasmas: A Unified Analytic Closure

  Open MIND · 2026-01-28

  preprint1st authorCorresponding

  In thermally non-equilibrium plasmas, conventional harmonic models can significantly mispredict superelastic electron heating rates. When the vibrational temperature exceeds the gas temperature ($T_{\rm v}>T_{\rm g}$), these models underestimate energy transfer by several times; conversely, they overestimate heating when $T_{\rm g}>T_{\rm v}$. We show that this discrepancy arises from neglecting the exponential heating from overpopulated, high-lying states in anharmonic Treanor-Gordiets distributions, and their thermodynamic depopulation at high gas temperatures. To resolve this, we derive a closed-form, thermodynamically consistent macroscopic closure based on detailed balance and a second-order Dunham expansion. This unified framework introduces an analytic anharmonic correction factor that captures the kinetic competition between vibrational-vibrational (V-V) up-pumping and vibrational-translational (V-T) relaxation. By predicting the Treanor minimum, this formulation recovers the fidelity of full state-to-state kinetic benchmarks. Ultimately, this model provides a governing equation for heat exchange between electrons and excited states in non-equilibrium environments -- including plasma-assisted combustion and hypersonic flows -- enabling the development of accurate, rate-limited reduced-order models for macroscopic fluid solvers.

  DOI

• Thermodynamically consistent vibrational–electron heating: Generalized model for multi-quantum transitions

  Physics of Fluids · 2026-01-01 · 1 citations

  articleOpen access1st authorCorresponding

  Accurate prediction of electron temperature (Te) is critical for non-equilibrium plasma applications ranging from hypersonic flight to plasma-assisted combustion (PAC). We recently proposed a thermodynamically consistent model for vibrational–electron heating [Rodriguez Fuentes and Parent, “Vibrational–electron heating in plasma flows: A thermodynamically consistent model,” Phys. Fluids 37, 096141 (2025)] that enforces the convergence of Te to the vibrational temperature (Tv) at equilibrium. However, the original derivation was restricted to single-quantum transitions, limiting its validity to low-temperature regimes (Te≲1.5 eV). In this Letter, we generalize the model to include multi-quantum overtone transitions, extending its applicability to high-energy regimes. We demonstrate that previous models neglecting hot-band transitions incur a systematic heating error of exp(−θv/Tv), where θv is the characteristic vibrational temperature. This error exceeds 40% when Tv is greater than θv, effectively preventing thermal relaxation. To correct this, we derive a formulation where the total heating rate is a summation of channel-specific cooling rates Qe−v(m), each associated with a quantum jump m, scaled by a thermodynamic factor exp(mθv/Te−mθv/Tv). This generalized model preserves thermodynamic consistency by ensuring zero net energy transfer at equilibrium.

  PublisherOA PDFDOI

• Superelastic heating in Treanor–Gordiets plasmas: A unified analytic closure

  The Journal of Chemical Physics · 2026-05-11

  articleOpen access1st authorCorresponding

  In thermally non-equilibrium plasmas, conventional harmonic models can significantly mispredict superelastic electron heating rates. When the vibrational temperature exceeds the gas temperature (Tv > Tg), these models underestimate energy transfer by several times; conversely, they overestimate heating when Tg > Tv. We show that this discrepancy arises from neglecting the exponential heating from overpopulated, high-lying states in anharmonic Treanor-Gordiets distributions and their thermodynamic depopulation at high gas temperatures. To resolve this, we derive a closed-form, thermodynamically consistent macroscopic closure based on detailed balance and a second-order Dunham expansion. This unified framework introduces an analytic anharmonic correction factor that captures the kinetic competition between vibrational-vibrational (V-V) up-pumping and vibrational-translational (V-T) relaxation. By predicting the Treanor minimum, this formulation recovers the fidelity of full state-to-state kinetic benchmarks. Ultimately, this model provides a governing equation for heat exchange between electrons and excited states in non-equilibrium environments-including plasma-assisted combustion and hypersonic flows-enabling the development of accurate, rate-limited reduced-order models for macroscopic fluid solvers.

  PublisherOA PDFDOI

• Thermodynamically Consistent Vibrational-Electron Energy Exchange and Application to Hypersonic Plasmas

  2026-01-08

  articleSenior author

  This paper investigates electron heating and cooling in hypersonic plasma flows by utilizing the new thermodynamically consistent vibrational-electron heating model that we recently derived in [F. M. Rodriguez Fuentes and B. Parent, Phys. Fluids 37, 096141 (2025)]. While adhering to this framework, we here introduce new spline fits for the reduced electric field as a function of electron temperature and plasma density for the vibrationally excited states of nitrogen N2(v = 1), N2(v = 2), and N2(v = 3). These fits, constructed via a synthesis of data from swarm experiments and collision cross-sections, reveal that vibrationally excited states enhance electron cooling by up to a factor of 10 in low plasma density regimes. However, this effect diminishes to a factor of 2–3 when the plasma density exceeds 0.01% and becomes negligible when the electron temperature is less than 5000 K. The resulting physical model is validated through numerical simulations of the RAM-C-II and OREX re-entry flight tests. The results demonstrate excellent agreement with experimental flight data regarding plasma density at altitudes between 61 and 81 km. Furthermore, the model accurately predicts the heat flux to the surface at the stagnation point for altitudes as high as 96 km.

  PublisherDOI

• Electron Density Depletion in Re-Entry Plasma Flows Using Pulsed Electric Fields

  ArXiv.org · 2025-12-20

  articleOpen accessSenior author

  Communication blackout due to the plasma layer creates a critical telemetry gap for re-entry vehicles. To mitigate this, we present the first fully-coupled simulation of high-voltage pulsed discharges interacting with a Mach 24 flowfield. The results demonstrate that the applied electric field generates a large, non-neutral plasma sheath near the cathode, depleting electron density by several orders of magnitude over a distance commensurate with the height of the shock layer. This depletion window effectively reduces the attenuation of a 4 GHz signal from 60% to 4% with a manageable power requirement of 66 W per cm$^2$ of exposed cathode surface. A sensitivity analysis reveals that the sheath topology is governed principally by ion kinetics; specifically, corrections to ion mobility at high reduced electric fields lead to enhanced space-charge shielding and a subsequent contraction of the sheath. Conversely, the sheath structure is largely insensitive to the electron mobility model. Finally, we argue that the present drift-diffusion model likely yields a conservative lower bound for mitigation performance. A kinetic approach accounting for ballistic ion transport and non-local ionization would likely predict thicker sheaths and lower attenuation for equivalent power deposition.

  PublisherOA PDF

• Vibrational-electron heating in plasma flows: A thermodynamically consistent model

  Physics of Fluids · 2025-09-01 · 5 citations

  articleOpen accessSenior author

  Accurate prediction of electron temperature (Te) in non-equilibrium plasma flows is critical, yet hampered by inadequate models for electron heating from vibrationally excited states. Prior models often relied on ad hoc scaling or flawed applications of detailed balance that failed to ensure the convergence of electron temperature and species-specific vibrational temperature (Tv) at thermal equilibrium. This paper introduces a novel, thermodynamically consistent electron heating model derived rigorously from the principle of detailed balance. By assuming a Boltzmann vibrational distribution and employing an effective activation energy, our approach yields a simple heating-to-cooling ratio of exp(θv/Te−θv/Tv), where θv is the characteristic vibrational temperature of the species under consideration. This formulation guarantees that Te correctly converges to Tv at equilibrium. A key advantage is that our model can utilize total cooling rates determined from swarm experiments, leading to higher accuracy at low electron temperatures. For reentry flows, the proposed approach predicts an electron temperature several times lower than previous models, which results in improved agreement with some flight test data. These more reliable predictions can significantly enhance the modeling fidelity of plasma-assisted combustion, laser-induced plasmas, and various hypersonic plasma technologies such as electron transpiration cooling or magnetohydrodynamic force generators.

  PublisherOA PDFDOI

• Electrodeless Magnetohydrodynamic Local Force Generator for Aerocapture

  AIAA Journal · 2025-06-01 · 5 citations

  articleOpen access1st authorCorresponding

  This paper presents a novel magnetohydrodynamics (MHD) system for planetary entry aerocapture. The following two features provide the system an advantage over earlier methods: i) it can be deployed locally to one or various flow regions, and ii) it does not make use of electrodes. Previous MHD systems for planetary entry were either electrodeless global systems or two-electrode local systems. The proposed novel MHD system employs two magnets to establish a current loop, resulting in a Faraday electromotive force. The first magnet is positioned to ensure that the magnetic field faces outward from the shell, while the second magnet is oriented to ensure that the magnetic field faces inward toward the shell. Preliminary findings demonstrate that when located on the surface of an Earth-entry capsule at a flight Mach number of 35, the novel electrodeless MHD system can generate forces several times greater than a two-electrode system while utilizing the same magnetic field strength. The study is conducted entirely through numerical simulation using Computational Fluid Dynamics, Waves, Reactions, Plasmas (CFDWARP), a computational fluid dynamics code that employs advanced numerical methods allowing for the full coupling between aerodynamics, magnetohydrodynamics, and non-neutral plasma sheaths. The physical model includes an 11-species finite-rate chemical solver, including real gas effects, and the drift-diffusion model for all charged species, along with an electric field potential equation that satisfies Gauss’s law.

  PublisherOA PDFDOI

• Electron Density Depletion in Reentry Plasma Flows Using Pulsed Electric Fields

  arXiv (Cornell University) · 2025-12-20

  preprintOpen accessSenior author

  Communication blackout due to the plasma layer creates a critical telemetry gap for re-entry vehicles. To mitigate this, we present the first fully-coupled simulation of high-voltage pulsed discharges interacting with a Mach 24 flowfield using an advanced numerical framework. The results demonstrate that the applied electric field generates a large, non-neutral plasma sheath near the cathode, depleting electron density by several orders of magnitude over a distance commensurate with the height of the shock layer. This depletion window effectively reduces the attenuation of a 4 GHz signal from 60% to 4% with a manageable power requirement of 66 W per cm$^2$ of exposed cathode surface. Feasibility analysis indicates that this system can be powered by a battery pack weighing less than 3 kg for a typical re-entry trajectory, with further mass reductions possible through intermittent transmission. A sensitivity analysis reveals that the sheath topology is governed principally by ion kinetics; specifically, corrections to ion mobility at high reduced electric fields lead to enhanced space-charge shielding and a subsequent contraction of the sheath. Conversely, the sheath structure is largely insensitive to the electron mobility model. Finally, we argue that the present drift-diffusion model likely yields a conservative lower bound for mitigation performance. A kinetic approach accounting for ballistic ion transport and non-local ionization would likely predict thicker sheaths and lower attenuation for equivalent power deposition.

  PublisherDOI

Frequent coauthors

• J. P. Sislian

  19 shared

• Sergey Macheret

  Purdue University West Lafayette

  16 shared

• Mikhail N. Shneider

  Princeton University

  11 shared

• Nobuhiro Harada

  9 shared

• 최정열

  7 shared

• Felipe Martín Rodríguez Fuentes

  6 shared

• Prasanna T. Rajendran

  University of Arizona

  6 shared

• In‐Seuck Jeung

  5 shared

Education

• Ph.D., Institute for Aerospace Studies

  University of Toronto

  2002

• M.A.Sc., Institute for Aerospace Studies

  University of Toronto

  1998

• B.Eng., Mechanical Engineering

  McGill University

  1996

Awards & honors

• Editor's Pick Physics of Fluids, AIP (American Institute of…
• Trusted Reviewer Award IOP (Institute of Physics), Spring 20…
• AIAA Associate Fellow American Institute of Aeronautics and…
• Editor's pick award Physics of Fluids, Spring 2022
• Best Paper of the Year Award AIAA, Spring 2021