Thermal radiation properties of PTFE plasma

Pulsed plasma thrusters (PPTs) are an attractive form of micro-thrusters due to advantages such as their compactness and lightweight design compared to other electric propulsion systems. Experimental investigations on their plasma properties are beneficial in clarifying the complex process of plasma evolution during the micro-second pulse discharge of a PPT. In this work, the multi-dimensional evolutions of the light intensity of the PPT plasma with wavelength, time, and position were identified. The plasma pressure was obtained using an iterative process with composition calculations. The results show that significant ion recombination occurred in the discharge channel since the line intensities of CII, CIII, CIV, and FII decreased and those of CI and FI increased as the plasma moved downstream. At the center of the discharge channel, the electron temperature and electron density were in the order of 10 000 K and 10 17 cm −3 , respectively. These had maximum values of 13 750 K and 2.3×10 17 cm −3 and the maximum temperature occurred during the first half-cycle while the maximum number density was measured during the second half-cycle. The estimated plasma pressure was in the order of 10 5 Pa and exhibited a maximum value of 2.69×10 5 Pa.

“…The theoretical model behind the component calculation [20] is composed of the Saha equation, quasi-neutrality equation, particle conservation relation, and the law of partial pressure.…”

Section: Variation In Plasma Pressure With Timementioning

confidence: 99%

Experimental investigation on the evolution of plasma properties in the discharge channel of a pulsed plasma thruster

Zhou

Wang

et al. 2020

“…Ablative pulsed plasma thruster (APPT), which has been developed since 1960s [1], is a kind of electric propulsion with high reliability and wide range of application. Compared with other kinds of electric propulsion, pulsed plasma thruster (PPT) has solid propellant known as poly tetra fluoroethylene (PTFE) [2] instead of a gas system [3], so it prevails in its simple configuration and low cost.…”

Section: Introductionmentioning

confidence: 99%

PIC simulation of plasma properties in the discharge channel of a pulsed plasma thruster with flared electrodes

Liu¹,

Yang²,

Huang³

2019

Plasma in the discharge channel of a pulsed plasma thruster (PPT) with flared electrodes is simulated by a self-developed two-dimensional code. The fully particle-in-cell method with Monte Carlo collision is employed to model the particle movement and collisions and investigate the plasma properties and acceleration process. Temporal and spatial variations of the electron density distribution and the ion velocity between electrodes are calculated and analyzed in detail. The computational results of the electron number density, which is in the order of 10 23 m −3 , show good agreements with experimental results of a PPT named ADD SIMP-LEX. The ion velocity distributions along the center line of the channel lead to a comprehensive understanding of ions accelerated by electromagnetic field. The electron distributions of PPT with discharge voltages varying from 1300 to 2000 V are compared. The diffusion of electrons presents strong dependency on discharge voltage and implies higher degree of ionization for higher voltage.

“…Another way is to change the plasma target configuration, such as one or multiple laser interaction with near-critical-density plasma [28][29][30][31], solid Al target [32][33][34] or gas plasma [35,36]. Among them, laser wakefield acceleration [37] and laser ponderomotive acceleration [38,39] are generally used to enhance electron acceleration and constraint. Recently, the radiation pressure acceleration (RPA) of ultra-thin foils is also applied to γ-ray emission and dense e + e − pairs production [40], as it is capable of obtaining high energy electrons and quasi-monoenergetic ion beams [41][42][43][44].…”

Section: Introductionmentioning

confidence: 99%

High density γ-ray emission and dense positron production via multi-laser driven circular target

Hou¹,

Xie²,

Lv³

et al. 2019

A diamond-like carbon circular target is proposed to improve the γ-ray emission and pair production with lasers intensity of 8 × 10 22 W/cm 2 by using two-dimensional particle-in-cell simulations with quantum electrodynamics. It is found that the circular target can significantly enhance the density of γ-photons than plane target when two colliding circularly polarized lasers irradiate the target. By multi-lasers irradiate the circular target, the optical trap of lasers can prevent the high energy electrons accelerated by laser radiation pressure from escaping. Hence, high density as 5164n c γ-photons is obtained through nonlinear Compton back-scattering. Meanwhile, 2.7 × 10 11 positrons with average energy of 230 MeV is achieved via multiphoton Breit-Wheeler process. Such ultrabright γ-ray source and dense positrons source can be useful to many applications. The optimal target radius and laser mismatching deviation parameters are also discussed in detail.