Critical regimes and magnetohydrodynamic instabilities in a magneto-plasma-dynamic thruster

Zuin, M.; Cavazzana, R.; Martines, E.; Serianni, G.; Antoni, V.; Bagatin, M.; Andrenucci, Mariano; Paganucci, Fabrizio; Rossetti, P.

doi:10.1063/1.1786593

Cited by 17 publications

(12 citation statements)

References 17 publications

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“…This fact has been shown by means of axial flux measurements performed in experimental conditions similar to those analyzed in this paper. 7 An identical paramagnetic behavior is seen also in plasma guns, 29 and has a nice analogy with the spontaneous nonaxisymmetric processes ͑often referred to as "dynamos"͒ that sustain some laboratory toroidal plasma configurations, such as spheromaks 30 and reversed-field pinches. 31,32 The exact calculation of the additional current carried by the kink is ongoing work, and it is crucial for understanding the thrust limitations arising in onset conditions.…”

Section: Tomographic Imaging In the Uv Regionmentioning

confidence: 83%

“…6 The limitation of the thrust efficiency has, therefore, been linked to the Kruskal-Shafranov limit. 6,7 Usually, the presence of a large MHD instability affects the current profile, and locally modifies the density and temperature of the plasma. Since radiation emitted by the plasma is a strong function of density and temperature, its measurements are a good tool for detecting the presence of large deformation of the plasma column.…”

Section: Introductionmentioning

confidence: 99%

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Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

et al. 2005

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In this paper the results of a project concerning the ultraviolet ͑UV͒ imaging of a plasma for space applications, produced in a magneto-plasmadynamic ͑MPD͒ thruster, are presented. MPD are a class of high-power electric space propulsion devices that accelerate a plasma to high velocities ͑Ͼ10 km/ s͒, by exploiting the Lorentz force. This force arises from the interaction between the discharge electrical current and a self induced and externally applied magnetic field. The imaging system has been realized by inserting three arrays of UV-enhanced photodiodes directly into the plastic structure of the anode. The amplifiers are miniaturized and built into the detector. This advanced diagnostic design allows for a detailed tomographic reconstruction of the emissivity spatial structure, both in the axial direction z ͑corresponding to a wave number n͒ and azimuthal direction ͑wave number m͒ with high time resolution. A magneto-hydrodynamic instability, with mode numbers m = 1 and n = 1 has been observed, which might affect the performances of the thruster.

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Section: Tomographic Imaging In the Uv Regionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

et al. 2005

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“…Spheromak technology has been used at Caltech to make jets with kilogauss fields, time scales of tens of microseconds, and tens of cm characteristic lengths [22][23][24] and this technology has also been used at Caltech to simulate solar coronal loops and show 25,26 that MHD jets are an important aspect of these loops. MHD jets have also been investigated as the basis for spacecraft propulsion at the Consorzio RFX in Italy by Zuin et al 27 and at Princeton University by Lev and Choueiri. 28 The above list of situations where MHD jets occur spans twenty orders of magnitude in time and space; yet, these situations have the same morphology, topology, and dynamical mechanism.…”

Section: Introductionmentioning

confidence: 99%

Experiments and models of MHD jets and their relevance to astrophysics and solar physics

Bellan

2018

Physics of Plasmas

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Magnetohydrodynamic (MHD)-driven jets involve poloidal and toroidal magnetic fields, finite pressure gradients, and unbalanced forces. The mechanism driving these jets is first discussed qualitatively by decomposing the magnetic force into a curvature and a gradient component. The mechanism is then considered quantitatively by consideration of all terms in the three components of the MHD equation of motion and in addition, the implications of Ampere's law, Faraday's law, the ideal Ohm's law, and the equation of continuity. The analysis shows that jets are self-collimating with the tip of the jet moving more slowly than the main column of the jet so there is a continuous stagnation near the tip in the jet frame. Experiments supporting these conclusions are discussed and it is shown how this mechanism relates to jets in astrophysical and solar corona contexts.

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“…MHD kink modes are also observed in laboratory Z-pinch [7] and tokamak plasmas, and during spheromak formation are thought to mediate the conversion of toroidal to poloidal magnetic flux [8,9]. In the applied field magneto-plasma thruster, the kink instability appears to deteriorate the performance of the thruster at high current [10,11] and methods to suppress it are highly desirable [12].…”

Section: Introductionmentioning

confidence: 99%

“…(8), ( 11) in the case of small super-criticality, we introduce the following dimension-less variables (denoted by the wave):…”

Section: Appendix: Effect Of Flow At Modest-to-high Mach Numbers Nearmentioning

confidence: 99%

Effects of boundary conditions and flow on the kink instability in a cylindrical plasma column

et al. 2007

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An experimental investigation of the kink instability is presented in a linear plasma column where one end is line-tied to the plasma source, and the other end is not line-tied and therefore free to slide over the surface of the end-plate. This latter boundary condition is a result of plasma sheath resistance that insulates, at least partially, the plasma from the end-plate. The helical m = 1 kink mode is observed to grow when the plasma current exceeds a threshold and, close to the criticality, is characterized by an axial mode structure with maximum displacement at the free axial boundary. Azimuthal rotation of the mode is observed such that the helically kinked column always screws into the free axial boundary. The kink mode structure, rotation frequency and instability threshold are accurately reproduced by a recent kink theory [D. D. Ryutov, et al., Phys. Plasmas 13, 032105 (2006)], which includes axial plasma flow and one end of the plasma column that is free to move due to a perfect non-line-tying boundary condition which is experimentally verified. A brief review of the kink theory and its predictions for the boundary conditions relevant in the present experiments are presented.

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Critical regimes and magnetohydrodynamic instabilities in a magneto-plasma-dynamic thruster

Cited by 17 publications

References 17 publications

Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

Ultraviolet tomography of kink dynamics in a magnetoplasmadynamic thruster

Experiments and models of MHD jets and their relevance to astrophysics and solar physics

Effects of boundary conditions and flow on the kink instability in a cylindrical plasma column

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