We study electric field quench in N=2 strongly coupled gauge theory, using the AdS/CFT correspondence. To do so, we consider the aforementioned system which is subjected to a time-dependent electric field indicating an out of equilibrium system. Defi
ning the equilibration time t_{eq}, at which the system relaxes to its final equilibrium state after injecting the energy, we find that the rescaled equilibriation time k^{-1}t_{eq} decreases as the transition time k increases. Therefore, we expect that for sufficiently large transition time, k ->infinity, the relaxation of the system to its final equilibrium can be an adiabatic process. On the other hand, we observe a universal behavior for the fast quenches, k << 1, meaning that the rescaled equilibration time does not depend on the final value of the time-dependent electric field. Our calculations generalized to systems in various dimensions also confirm universalization process which seems to be a typical feature of all strongly coupled gauge theories that admit a gravitational dual.
The effects of both elliptical shape and stage of emergence of the coronal loop on the resonant absorption of standing kink oscillations are studied. To do so, a typical coronal loop is modeled as a zero-beta longitudinally stratified cylindrical mag
netic flux tube. We developed the connection formulae for the resonant absorption of standing transversal oscillations of a coronal loop with an elliptical shape, at various stages of its emergence. Using the connection formulae, the dispersion relation is derived and solved numerically to obtain the frequencies and damping rates of the fundamental and first-overtone kink modes. Our numerical results show that both the elliptical shape and stage of emergence of the loop alter the frequencies and damping rates of the tube as well as the ratio of frequencies of the fundamental and its first-overtone modes. However, the ratio of the oscillation frequency to the damping rate is not affected by the tube shape and stage of its emergence and also is independent of the density stratification parameter.
The standing quasi-modes of the ideal MHD in a zero-$beta$ cylindrical magnetic flux tube that undergoes a longitudinal density stratification and radial density structuring is considered. The radial structuring is assumed to be a linearly varying de
nsity profile. Using the relevant connection formulae of the resonant absorption, the dispersion relation for the fast MHD body waves is derived and solved numerically to obtain both the frequencies and damping rates of the fundamental and first-overtone, $k=1,2$ modes of both the kink ($m=1$), and fluting ($m=2$) waves. Where $k$ and $m$ are the longitudinal and azimuthal mode numbers, respectively.
