  An electron plasma can be confined for a theoretically infinite time in a
Penning-Malmberg trap, a linear, azimuthally-symmetric magneto-electrostatic
device where upon suitable conditions (high magnetization) the transverse
dynamics of the plasma column is isomorphic to the one displayed by a
two-dimensional ideal fluid. Fluid dynamics can thus be reproduced in these
systems with a very high degree of control on the system's parameters and
active excitation of fluid perturbations is made possible by the use of static
or time-dependent electric fields (i.e., fluid strains) imparted by electric
potentials applied to the azimuthal patches of a sectored electrode of the
trap. An example is represented by azimuthal velocity shear phenomena and the
insurgence of Kelvin-Helmholtz (KH) instabilities in fluid vortices. We present
a study where we exploit multipolar rotating electric fields to generate
V-states and observe their dynamics and stability properties. A V-state is the
generalization of the 2D Kirchhoff (elliptical) fluid vortex to a generic KH
mode, in the nonlinear regime. In particular, we discuss first how we can
exploit a combination of techniques (plasma evaporation and tilt-induced
transport) to tune the radial vorticity profile, which may have an effect on
the dynamics of the growth and decay of the selected KH wave. We also
investigate autoresonant (swept-frequency, self-locking) excitation - useful,
e.g., for the precise control of the KH mode growth - and discuss the features
of autoresonance applied to higher-order KH waves.
