Design study of a combined interferometer and polarimeter for a high-field, compact tokamak

Creely, A. J.; Milanese, Lucio M.; Tolman, Elizabeth A.; Irby, J.; Ballinger, S.; Frank, Samuel; Kuang, Adam; Linehan, B.; McCarthy, W.; Montes, Kevin; Mouratidis, Theodore; Picard, Julian; Rodriguez-Fernandez, P.; Rosenthal, Aaron; Sandberg, Alexander; Sciortino, Francesco; Simpson, Raspberry; Tinguely, R. A.; Zhou, Muni; White, Anne

doi:10.1063/1.5142638

Cited by 4 publications

(1 citation statement)

References 33 publications

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“…Interferometers and Polarimeters are well-assessed tools, developed for plasma diagnostics in thermonuclear fusion machines (Zhang et al, 2012;Tudisco et al, 2013;Creely et al, 2020) to measure both line-averaged density and magnetic field, also in the so called "InterPol" combined setups. In compact electron cyclotron resonance (ECR) ion sources (ECRIS) this is a challenging task due to the extremely tenuous plasma (if compared to densities of thermonuclear fusion reactor plasmas) and to their compact size.…”

Section: Introductionmentioning

confidence: 99%

Mm-wave polarimeter and profilometry design study for retrieving plasma density in the PANDORA experiment

Torrisi

Naselli²,

Donato³

et al. 2022

Front. Astron. Space Sci.

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In the recent past, the possibility to use a superconducting trap confining a hot and dense plasma as a tool to investigate radioactivity in astrophysical scenarios has been proposed. Making possible these kind of unprecedented measurements is the main aim of the PANDORA (Plasmas for Astrophysics Nuclear Decays Observation and Radiation for Archaeometry) project. In this context, it is planned to build a compact and flexible magnetic plasma trap where plasma reaches an electron density ne ∼ 1011–1013 cm−3, and an electron temperature, in units of kT, kTe ∼ 0.1–30 keV. The setup is conceived to be able to measure, for the first time, nuclear β-decay rates in stellar-like conditions in terms of ionization states. In this paper, the design study of a mm-wave polarimeter for the PANDORA plasma line-integrated electron density measurement is presented. The paper highlights the method of this type of measurements for the first time proposed for a magneto-plasma trap which represents an “intermediate” case between the ultra-compact plasma ion sources and the large-size thermonuclear fusion devices. Preliminary measurements at scaled microwave frequencies have carried out both on a “free-space” setup by using a wire-grid polarizer and a rotable Ka-band OMT + horn antennas system, and on a compact trap (called Flexible Plasma Trap) installed at INFN-LNS and used as PANDORA down-sized testbench are described. The polarimeter technique will support β-decay investigation by simultaneous measurements of the total plasma density, which is crucial to carefully evaluate the decay-constant and to extrapolate the laboratory observed data to the astrophysical scenarios. Moreover, this work proposes to adopt an electromagnetic inverse-scattering-based technique-based method to retrieve the electron density profile along the probing antennas line-of-sight. Numerical results of this so-called “inverse profilometry” are also shown.

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Section: Introductionmentioning

confidence: 99%

Mm-wave polarimeter and profilometry design study for retrieving plasma density in the PANDORA experiment

Torrisi

Naselli²,

Donato³

et al. 2022

Front. Astron. Space Sci.

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ITER Toroidal Interferometer and Polarimeter (TIP) beam refraction in 3D density profiles

Zeeland

Akiyama

Bécoulet

et al. 2023

Fusion Engineering and Design

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Microwave techniques for electron cyclotron resonance plasma diagnostics

Naselli

Torrisi

2022

Review of Scientific Instruments

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This paper reviews the main microwave diagnostic techniques and tools adopted in electron cyclotron resonance (ECR) (and others) ion source laboratories, with a special focus on techniques and instruments developed at INFN-LNS. Along with the tools used for optimization of microwave launching (power monitors, spectral analysis, and network analyzers), this paper deals, in particular, with more recent devices on-purpose developed to perform in-plasma analysis, such as absolute density measurements and density profiles retrieval. Among these, the first example of microwave interferometry for ECR compact machines (the VESPRI interferometer at INFN-LNS) will be briefly discussed, in combination with microwave polarimetric techniques based on Faraday rotation detection. More sophisticated microwave techniques are going to be designed and are now at a numerical study stage, e.g., profilometry and imaging via inverse scattering methods (this paper will offer short theoretical bases and first numerical results on 1D profilometry). In the end, the relevance about the implications and interplays of microwave techniques in multidiagnostic systems (microwave, optical, and x-ray domains) will be commented, with a special focus on time resolved microwave measurements and advanced signal processing via wavelet transform, useful for characterization of plasma instabilities.

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Design study of a combined interferometer and polarimeter for a high-field, compact tokamak

Cited by 4 publications

References 33 publications

Mm-wave polarimeter and profilometry design study for retrieving plasma density in the PANDORA experiment

Mm-wave polarimeter and profilometry design study for retrieving plasma density in the PANDORA experiment

ITER Toroidal Interferometer and Polarimeter (TIP) beam refraction in 3D density profiles

Microwave techniques for electron cyclotron resonance plasma diagnostics

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