Plasma dynamics in a helicon thruster

A two-dimensional, full-wave, frequency domain, cold plasma model is used to study electromagnetic power propagation and absorption in a helicon plasma thruster, including its far plume region and surrounding space. Results show that a fraction of power is absorbed in the plume region, and that power deposition in the source is essentially unperturbed by the simulation domain size, the presence of metallic obstacles, nor the plasma density in the environment. An electron-cyclotron resonance (ECR) surface always exists downstream that effectively prevents radiation to the space beyond. In the presence of an overdense environmental plasma, like the one expected in a vacuum chamber, fields are fully evanescent beyond this transition, and vacuum chamber boundary conditions affect little the wavefields before this surface. In the absence of an environmental plasma, a double transition exists at the interface between the plasma and vacuum that hinders accurate numerical simulation in the plume region.

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“…Helicon Plasma Thrusters (HPTs) are electric propulsion devices currently under research and development [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Wave propagation and absorption in a helicon plasma thruster and its plume

Pedro

Merino

Ahedo

2022

Plasma Sources Sci. Technol.

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“…The helicon plasma thruster (HPT) is an innovative technology for space propulsion, which, at present, is being researched extensively. [1][2][3][4][5][6][7] The device is constituted of a helicon source, where the plasma is generated and heated, and an external divergent magnetic nozzle, where the plasma is accelerated. The physical elements of a HPT are: a cylindrical dielectric chamber; a gas injection system, usually at the back of the chamber; an external antenna wrapped around the chamber and emitting rf waves, typically in the range 1-26 MHz, which propagate within the plasma; and a set of magnetic coils (or permanent magnets) that creates a longitudinal magnetic field, typically in the range 10 2 to 10 3 Gauss.…”

Section: Introductionmentioning

confidence: 99%

Helicon thruster plasma modeling: Two-dimensional fluid-dynamics and propulsive performances

2013

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An axisymmetric macroscopic model of the magnetized plasma flow inside the helicon thruster chamber is derived, assuming that the power absorbed from the helicon antenna emission is known. Ionization, confinement, subsonic flows, and production efficiency are discussed in terms of design and operation parameters. Analytical solutions and simple scaling laws for ideal plasma conditions are obtained. The chamber model is then matched with a model of the external magnetic nozzle in order to characterize the whole plasma flow and assess thruster performances. Thermal, electric, and magnetic contributions to thrust are evaluated. The energy balance provides the power conversion between ions and electrons in chamber and nozzle, and the power distribution among beam power, ionization losses, and wall losses. Thruster efficiency is assessed, and the main causes of inefficiency are identified. The thermodynamic behavior of the collisionless electron population in the nozzle is acknowledged to be poorly known and crucial for a complete plasma expansion and good thrust efficiency. V

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“…In radio-frequency electrothermal thrusters, the plasma is contained within a discharge chamber. This chamber is typically a cylindrical tube of quartz or Pyrex (trade name for a borosilicate glass), due to their low loss dielectric and thermal properties [12]. As has been previously mentioned, the plasma within the discharge chamber is excited by a radio-frequency electromagnetic field, produced by a coiled antenna.…”

Section: Principles Of Electrothermal Thruster Operationmentioning

confidence: 99%

“…Circuit ConstructionTwelve(12) AWG silver plated copper wire was soldered to the center conductor of the RG65 coaxial cable running from the RF power supply, using the lead-free solder. The wire was then threaded through a hole in the matching network chassis and soldered to the positive terminal of the capacitor.…”

mentioning

confidence: 99%