Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

Bonomo, F.; Franz, P.; Spizzo, G.; Marrelli, L.; Martin, P.; Paganucci, Fabrizio; Rossetti, P.; Signori, M.; Andrenucci, Mariano; Pomaro, N.

doi:10.1063/1.2012108

Cited by 8 publications

(4 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In terms of a three-dimensional (helical) structure of the mode this corresponds, at 70 kHz (which is the dominant frequency in this case), to an estimated axial wavelength λ z (=f −1 z/ t) of the mode of ∼20 cm, comparable to the axial system dimension. This result is in good agreement with observations made with ultraviolet tomography, which allows a three-dimensional imaging of the kink, by starting from the emissivity of the section C and interpreting a temporal sequence at a fixed z position as a spatial scan of an iso-emissive surface at a fixed time [20]. The final 3D mapping can be seen in figure 8, which shows an emissive helical structure in the axial direction originating at the outer cathode surface and expanding toward the anode, thus following the conical geometry of field lines.…”

Section: Plasma Fluctuation Propertiessupporting

confidence: 89%

MHD instabilities in magneto-plasma-dynamic thrusters

Paganucci

Zuin

Agostini

et al. 2008

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Magneto-plasma-dynamic thrusters (MPDTs) act as electromagnetic plasma accelerators and represent a high power, electric propulsion option for primary space missions. One of the major problems facing MPDT operation is the onset of a critical regime, which is found when the power is increased beyond a threshold value, depending mainly on the thruster geometry, the type and mass flow rate of the propellant and the intensity of the magnetic field applied. In this regime, large fluctuations in the electrode voltage signals, damage to the anode and decreased efficiency are observed. Since 2000, several test campaigns have been carried out to investigate the electrostatic and magnetic properties of plasma fluctuations using electromagnetic and optic probes and ultraviolet tomography. Results obtained have shown a strong relation between the onset phenomena and the growth of a large scale magnetohydrodynamic (MHD) instability, with helical kink mode features. On the basis of the experimental observations, a passive method to suppress instability is proposed and has been partially tested, with encouraging results.

show abstract

Section: Plasma Fluctuation Propertiessupporting

confidence: 89%

MHD instabilities in magneto-plasma-dynamic thrusters

Paganucci

Zuin

Agostini

et al. 2008

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…Since Cormak's invention [1,2], computer tomography has been widely used to reconstruct internal structures from their line-integrated projections initially for medical imaging of the human body. This non-invasive diagnostic technique is recently applied to plasma diagnostics; for example, reconstruction of x-ray emission of tokamak plasmas during their sawtooth crashes [3] and reconstruction of the kink instability in a magnetoplasmadynamic thruster [4].…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional ion temperature measurement by application of tomographic reconstruction to Doppler spectroscopy

et al. 2013

View full text Add to dashboard Cite

A novel 2D ion temperature measurement for toroidal plasmas has been developed by use of cost-effective discrete tomography reconstruction of 2D ion Doppler spectroscopy composed of a polychromator with an ICCD camera and optical fibres. The 2D projection of the line spectrum collected by 35 (7 × 5) optical fibres is transformed into the r-z profile of the local spectrum by means of the Abel inversion at each wavelength and finally into the 2D (r-z) profile of the ion temperature. Numerical tests of its algorithm indicate that the reconstruction error for a peaked temperature profile is smaller than 15% if the chord-integrated signals have noise smaller than 5%. This system successfully measured the peaked ion temperature profile of a torus plasma on the r-z plane under the condition of negligibly small plasma flow.

show abstract

“…It can be used also in small plasma devices, e.g. for producing 3D images of the plume of a plasma thruster for space propulsion applications [19,20]. Finally, visible tomography can be adopted to characterize a beam obtained from negative ions [21][22][23][24].…”

Section: Introduction: Tomography and Its Application To The Mitica Beammentioning

confidence: 99%

The tomographic diagnostic of ITER neutral beam injector

Brombin¹,

Agostini²,

Dianin³

et al. 2013

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

The two-dimensional (2D) density distribution of a particle beam can be reconstructed using a diagnostic based on tomographic techniques, which measures the Dα light. This paper presents investigations and tests concerning the reliability of such a diagnostic, applied to the beam produced in MITICA (Megavolt ITER Injector & Concept Advancement) the full-size prototype of the neutral beam injector, which will be used for additional heating on ITER. It aims at developing the technologies to guarantee the correct operation of the injectors to be installed in ITER. The main target of the tomographic diagnostic is the measurement of the beam uniformity with sufficient contrast and spatial resolution, and of its evolution throughout the pulse duration. In particular the ITER beam uniformity is required to be within 10%, thus the error of the tomographic reconstruction has to be lower than this value. The conceptual design of the diagnostic is presented, with a description of the layout and main components. The portholes around the vessel and the geometry of the lines of sight are arranged so as to cover the whole area of the beam. A tomographic algorithm based on the simultaneous algebraic reconstruction technique (SART) is developed to reconstruct the beam intensity profile. Phantoms reproducing different experimental beam configurations are simulated and reconstructed with this technique. The role of noise in the line-integrated signals is studied and its effect on the reconstructed emission is investigated. The unsatisfactory results suggested the introduction of a regularization algorithm, to reduce the effect of the noise in the beam reconstruction. In this way, the simulated phantoms are correctly reconstructed and their 2D spatial non-uniformity is correctly estimated, up to a noise level of 10%.

show abstract

Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

Cited by 8 publications

References 25 publications

MHD instabilities in magneto-plasma-dynamic thrusters

MHD instabilities in magneto-plasma-dynamic thrusters

Two-dimensional ion temperature measurement by application of tomographic reconstruction to Doppler spectroscopy

The tomographic diagnostic of ITER neutral beam injector

Contact Info

Product

Resources

About