Plasma-beam traps and radiofrequency quadrupole beam coolers

Maggiore, M.; Cavenago, M.; Comunian, M.; Chirulotto, F.; Galatà, A.; Lazzari, M. De; Porcellato, A.M.; Roncolato, C.; Stark, S.; Caruso, Antonio; Longhitano, Alberto; Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R.; Romé, M.

doi:10.1063/1.4830357

Cited by 26 publications

(19 citation statements)

References 10 publications

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“…, where H denotes the Heaviside step function, and r − and r + are the inner and outer radius of the ring, respectively, with r − /R w = 0.3724, r + /R w = 0.46. The following parameters are fixed in all simulations: n 0 = 10 7 cm −3 , R w = 2 cm, and B = 1 T [67,68,51]. In addition, the final time is 4 ms, and the time step is 10 −7 s.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Coherent structures and turbulence evolution in magnetized non-neutral plasmas

Romé

Chen²,

Maero

2018

AIP Conference Proceedings

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The evolution of turbulence of a magnetized pure electron plasma confined in a Penning-Malmberg trap is investigated by means of a two-dimensional particle-in-cell numerical code. The transverse plasma dynamics is studied both in the case of free evolution and under the influence of non-axisymmetric, multipolar radio-frequency drives applied on the circular conducting boundary. In the latter case the radio-frequency fields are chosen in the frequency range of the low-order azimuthal (diocotron) modes of the plasma in order to investigate their effect on the insurgence of azimuthal instabilities and the formation and evolution of coherent structures, possibly preventing the relaxation to a fully-developed turbulent state. Different initial density distributions (rings and spirals) are considered, so that evolutions characterized by different levels of turbulence and intermittency are obtained. The time evolution of integral and spectral quantities of interest are computed using a multiresolution analysis based on a wavelet decomposition of density maps. Qualitative features of turbulent relaxation are found to be similar in conditions of both free and forced evolution, but the analysis allows one to highlight fine details of the flow beyond the self-similarity turbulence properties, so that the influence of the initial conditions and the effect of the external forcing can be distinguished. In particular, the presence of small inhomogeneities in the initial density configuration turns out to lead to quite different final states, especially in the presence of competing unstable diocotron modes characterized by similar growth rates.

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Section: Numerical Simulationsmentioning

confidence: 99%

Coherent structures and turbulence evolution in magnetized non-neutral plasmas

Romé

Chen²,

Maero

2018

AIP Conference Proceedings

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“…The simulations presented here have been performed using a set of parameters similar to those of the future experiments with the DuEl apparatus [8] and suitable to describe the insurgence of the diocotron (Kelvin-Helmholtz) instability in the magnetized electron plasma and the influence of a dust contamination on its development. Zero potential is assumed on a circular boundary with radius R w = 20 mm, inscribed in a square domain discretized by 257 × 257 nodes.…”

Section: Numerical Investigationsmentioning

confidence: 99%

“…This is the subject of the "DuEl" (Dust-Electron) project [8], which comprises the realization of a suitably modified Penning-Malmberg trap for the confinement of such a system. We describe here the present status of the apparatus.…”

Section: Introductionmentioning

confidence: 99%

Effects of dust contamination on the transverse dynamics of a magnetized electron plasma

Romé¹,

Cavaliere²,

Cavenago³

et al. 2015

AIP Conference Proceedings

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Abstract. Complex (dusty) plasmas are characterized by the presence of a fraction of micrometric or sub-micrometric particles which may collect a surface charge up to the order of a few thousand electron charges. The dusty plasmas studied in the experiments generally satisfy a global neutrality condition. By contrast, we present here the investigation of a magnetized nonneutral plasma, i.e., a plasma with a single sign of charge (e.g. electrons) confined in a Penning-Malmberg trap, contaminated by a dust population. We simulate the two-dimensional transverse dynamics of this multi-component plasma with a particle-in-cell code implementing a mass-less fluid (drift-Poisson) approximation for the electrons and a kinetic description for the dust component (including gravity). Simulations with different initial dust distributions and densities have been performed in order to investigate the influence of the dust on the development of the diocotron instability in the electron plasma. In particular, the early stage of the growth of the diocotron modes has been analyzed by Fourier decomposition.

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“…We can cite, for instance, traps where particles of different species or even different signs are present, either due to background gas ionization (and hence being unwanted) or because their simultaneous confinement is required. Examples include formation of antimatter, trapping and cooling of multispecies or dust-contaminated particle samples and plasmas, 30,31 ion pumps. 32 Another case is represented by systems where the equilibrium is strongly altered by external perturbations like RF excitations.…”

Section: Introductionmentioning

confidence: 99%

Diocotron modulation in an electron plasma through continuous radio-frequency excitation

et al. 2014

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The application of a radio-frequency (RF) excitation to any electrode of a Penning-Malmberg trap may result in significant electron heating and ionization of the residual gas with the formation of a plasma column when the RF frequency is of the order or larger than the typical axial bounce frequencies of few-eV electrons. The use of a quadrupolar excitation can induce additional phenomena, like formation of dense, narrow-cross section columns which exhibit an mθ=1 diocotron mode, i.e., a rotation of their center around the trap axis. A series of experiments is presented and discussed showing that the continuous application of such excitation causes a dramatic perturbation of the plasma equilibrium also involving continuous production and loss of particles in the trapping region. In particular, the growth of the first diocotron mode is suppressed even in the presence of ion resonance and resistive instability and the mode exhibits steady-state or underdamped amplitude and frequency modulations, typically in the Hertz range.

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Plasma-beam traps and radiofrequency quadrupole beam coolers

Cited by 26 publications

References 10 publications

Coherent structures and turbulence evolution in magnetized non-neutral plasmas

Coherent structures and turbulence evolution in magnetized non-neutral plasmas

Effects of dust contamination on the transverse dynamics of a magnetized electron plasma

Diocotron modulation in an electron plasma through continuous radio-frequency excitation

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