Speaker
Massimiliano Romé
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.4003.pdf
Resonant excitation of high-order diocotron modes with rotating RF fields
M. Romé1,2 , G. Maero1,2 , N. Panzeri1,2 , R. Pozzoli1
1 Dipartimento di Fisica, Università degli Studi di Milano, Italy
2 INFN Sezione di Milano, Italy
The ability to excite and control low-frequency diocotron (Kelvin-Helmholtz) perturbations
in a magnetized nonneutral plasma goes beyond the obvious interest in the attainment of long-
time, stable confinement of a charged particle species. Indeed it represents an opportunity to
study dynamical properties of turbulent two-dimensional fluids [1, 2, 3], and recent investiga-
tions have directed attention to the behaviour of strained flows under the action of externally
imposed perturbations [4, 5].
In a Penning-Malmberg device, diocotron waves are typically excited by means of suitable
multipolar radio-frequency drives applied on an azimuthally sectored electrode of the trap at
the resonance frequency of the desired wavenumber. This scheme is limited by the number N of
electrically insulated azimuthal sectors of the electrode, yielding modes with an order ≤ N/2.
Generalizing a previous work [6], it is demostrated both theoretically with a linearized 2D
drift-Poisson model and experimentally in the Penning-Malmberg trap ELTRAP [7] that it is
possible to overcome this limit and selectively excite high-order diocotron modes with applied
electric fields which are co- or counter-rotating with respect to the azimuthal plasma rotation
direction, by properly choosing the drive frequency and the phase difference between adjacent
sectors.
References
[1] M. Romé, S. Chen and G. Maero, Plasma Phys. Control. Fusion 59, 014036 (2017)
[2] S. Chen, G. Maero and M. Romé, J. Plasma Phys. 83, 705830303 (2017)
[3] M. Romé, S. Chen and G. Maero, AIP Conf. Proc. 1928, 020012 (2018)
[4] N.C. Hurst, J.R. Danielson, D.H.E. Dubin and C.M. Surko, Phys. Rev. Lett. 117, 235001 (2016)
[5] N.C. Hurst, J.R. Danielson and C.M. Surko, AIP Conf. Proc. 1928, 020007 (2018)
[6] G. Bettega, B. Paroli, R. Pozzoli and M. Romé, J. Appl. Phys. 105, 053303 (2009)
[7] G. Maero, S. Chen, R. Pozzoli and M. Romé, J. Plasma Phys. 81, 495810503 (2015)
