Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “plasma accelerators”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Design of a Plasma Injector for a Pulsed Plasma Accelerator

In recent years, a pulsed plasma accelerator has been proposed as a candidate stand-off driver for the formation of an imploding liner in magnetized target fusion. For a near-term physics exploratory experiment to study the feasibility of this standoff approach, a plasma accelerator has been proposed that requires the controlled introduction and preparation of the initial plasma for acceleration. This includes uniform injection of the propellant downstream of the breech with a high degree of ionization. The design of a plasma feed is presented, which injects a high conductivity, highly collisional propellant transverse to the conductor. The plasma injector is designed to establish an initial plasma with a moderate Hall parameter at the trailing edge of the plasma slug, high Hall parameter behind the slug for magnetic insulation, and a short diffusion length in comparison with characteristic dimensions of the plasma slug to avoid propellant loss at the trailing edge.

Cassibry, J. T.↗
NASA NTRS2009

Magnetic circuit for hall effect plasma accelerator

A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.

Manzella, David H.↗
DOE OSTI2026

Stable and tunable MeV $$\gamma$$-ray generation via dual-laser inverse Thomson scattering from a laser-plasma accelerator

Abstract Inverse Thomson scattering from laser-plasma accelerators offers a pathway to compact, tunable MeV $$\gamma$$ -ray sources for reduced-dose radiography and enhanced performance in nuclear resonance fluorescence (NRF)-based isotope identification. However, photon yield and spectral quality are often limited by constraints on interaction geometry and scatter-laser tunability. Here we demonstrate a MeV $$\gamma$$ -ray source based on a dual-laser inverse Thomson scattering configuration driven by a 100-TW laser-plasma accelerator. Electron beams tunable from 122 to 204 MeV with $$<5$$ mrad divergence and $$<1$$ mrad pointing stability generate $$\gamma$$ rays with peak energies from 276 keV to 1.2 MeV and yields up to $$2\times 10^{7}$$ photons per shot. By independently controlling the interaction position and the scatter-pulse duration, we experimentally match the scatter pulse to the walk-off-limited interaction length. Extending the scatter pulse to 200 fs increases photon production by approximately $$15\%$$ while maintaining operation in the linear Thomson regime, thereby preserving narrow spectral bandwidth and controlled radiation divergence. Radiographic characterization demonstrates MeV-level penetration and $$\approx 0.1$$ mm spatial resolution, while stable operation is sustained over multi-hour timescales across multiple days. These results show that interaction-length optimization provides a scalable strategy for improving photon yield, spectral control, and operational stability in compact laser-plasma-accelerator-driven $$\gamma$$ -ray sources.

Tsai, Hai-En↗
NASA NTRS2019

Pulsed Plasma Acceleration Modeling in Detonation and Deflagration Modes

Gas-fed electromagnetic pulsed plasma accelerators discharge electrical energy into a gas to ionize and electromagnetically accelerate propellant in the domain. Efforts to model pulsed accelerators have either assumed that the discharge is short and completely tran- sient, accelerating the gas by entraining it in a moving current sheet, or that the discharge is relatively long, establishing a stable quasi-steady current distribution pattern that accel- erates a plasma flowing through it. There have been pulsed plasma accelerator tests that appear to fit somewhere between these two bounds, exhibiting some properties that are associated with the purely transient devices while also showing others that are associated with quasi-steady-state plasma acceleration. A model is presented based upon the premise that all pulsed plasma accelerators first form an accelerating current sheet (detonation mode accelerator). Depending upon the pulse length and the gas conditions in the dis- charge channel, the plasma sheet may reach the end of the accelerator before the discharge has completed a full half-cycle, wherein the proposed model transitions to a quasi-steady description of the acceleration process (deflagration mode accelerator). A review of the entire model is presented, highlighting improvements and upgrades implemented to aid in the stability of the numerical scheme used to model the gas flow in the channel and an im- proved treatment of current sheet mass shedding, which adds gas to the wake of the sheet. The assumptions employed to model the transition from detonation to deflagration mode are presented and used to generate solutions to the governing equations. The modeling of the deflagration-mode under the present assumptions results in very low deflagration im- pulse bits relative to those obtained at the end of the detonation mode, implying that the present assumptions and modeling of the deflagration mode may not represent a fruitful approach.

Polzin, Kurt A.↗
NASA NTRS1987

Electron-cyclotron-resonance (ECR) plasma acceleration

A research effort directed at analytically and experimentally investigating electron-cyclotron-resonance (ECR) plasma acceleration is outlined. In addition, relevant past research is reviewed. Also, the prospects for application of ECR plasma acceleration to spacecraft propulsion are described. It is shown that previously unexplained losses in converting microwave power to directed kinetic power via ECR plasma acceleration can be understood in terms of diffusion of energized plasma to the physical walls of the accelerator. It is also argued that line radiation losses due to electron-ion and electron-atom inelastic collisions should be less than estimated in past research. Based on this new understanding, the expectation now exists that very efficient ECR plasma accelerators can be designed for application to high-specific-impulse spacecraft propulsion.

Sercel, Joel C.↗
NASA NTRS1971

Energy deposition in parallel-plate plasma accelerators

To appraise the ratio of energy deposition into kinetic and thermal modes in plasma accelerators, a parallel-plate plasma accelerator has been operated in the quasi-steady mode with current pulses in the range of 10 to 100 kilo-amperes (kA), durations of the order of one millisecond, and argon mass flows up to 100 grams/sec. From photographic observations, spectroscopic measurements of velocity and electron density, and pressure measurements with a fast-rise piezoelectric transducer it is found that, for currents between 50 and 90 kA, the accelerated argon plasma is supersonic with ion velocities of 5 to 6 kilometers/sec.

Dicapua, M. S.↗
DOE OSTI2023

Stability of the modulator in a plasma-modulated plasma accelerator

We explore the regime of operation of the modulator stage of a recently proposed laser-plasma accelerator scheme [Phys. Rev. Lett. 127, 184801 (2021)], dubbed the plasma-modulated plasma accelerator (P-MoPA). The P-MoPA scheme offers a potential route to high-repetition-rate, GeV-scale plasma accelerators driven by picosecond-duration laser pulses from, for example, kilohertz thin-disk lasers. The first stage of the P-MoPA scheme is a plasma modulator in which a long, high-energy “drive” pulse is spectrally modulated by copropagating in a plasma channel with the low-amplitude plasma wave driven by a short, low-energy “seed” pulse. The spectrally modulated drive pulse is converted to a train of short pulses, by introducing dispersion, which can resonantly drive a large wakefield in a subsequent accelerator stage with the same on-axis plasma density as the modulator. In this paper we derive the 3D analytic theory for the evolution of the drive pulse in the plasma modulator and show that the spectral modulation is independent of transverse coordinate, which is ideal for compression into a pulse train. We then identify a transverse mode instability (TMI), similar to the TMI observed in optical fiber lasers, which sets limits on the energy of the drive pulse for a given set of laser-plasma parameters. We compare this analytic theory with particle-in-cell (PIC) simulations and find that even higher energy drive pulses can be modulated than those demonstrated in the original proposal.

43 PARTICLE ACCELERATORS↗
NASA NTRS1969

Quasi-steady plasma acceleration.

Quasi-steady state plasma acceleration in coaxial electrode geometry during synchronized application of tailored pulses of mass flow and current

Clark, K. E.↗
NASA NTRS1965

Plasma accelerator Patent

Crossed-field plasma accelerator for laboratory simulation of atmospheric reentry conditions

Busemann, A.↗
NASA NTRS1970

Quasi-steady plasma acceleration

Quasi-steady state plasma acceleration in coaxial electrode geometry during synchronized application of tailored pulses of mass flow and current

Clark, K. E.↗