L. Bardóczi

55227296900

Publications - 3

Technical upgrade and first tests of the experimental device for quasi-2D turbulent electrolyte flow experiment

M. Berta L. Bardóczi E. Walcz L. Poszovecz A. Biricz A. Bencze

Publication Name: Fusion Engineering and Design

Publication Date: 2019-09-01

Volume: 146

Issue: Unknown

Page Range: 1899-1902

Description:

A major upgrade of the experimental device for quasi-2 dimensional turbulence studies in magnetized electrolyte system is presented. The development has been motivated by the preparation of envisaged new experiments to investigate the effect of boundary walls on 2D turbulence cascades and the study of small vortex interactions with large scale sheared flows. The latter problem is relevant in different basic scientific as well as applied areas such as the reduction of anomalous transport via shear flows in magnetically confined fusion plasmas. The hardware upgrade consists of: (a) significantly larger electrolyte tank able to accommodate up to 2500 permanent magnets and adjustable walls, (b) ensemble of an electronically driven solenoid and a configurable permanent magnet array, (c) highly automatic acquisition and control of the experimental data and parameters. A first experimental test of the upgraded device is also presented.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2019.03.060

Experimental confirmation of self-regulating turbulence paradigm in two-dimensional spectral condensation

M. Berta L. Bardóczi L. Schmitz A. Bencze

Publication Name: Physical Review E Statistical Nonlinear and Soft Matter Physics

Publication Date: 2014-12-03

Volume: 90

Issue: 6

Page Range: Unknown

Description:

Turbulent transport in magnetic fusion plasmas can be significantly suppressed by Reynolds-stress-induced zonal flows, allowing effective plasma confinement. We present experimental evidence of spatiotemporal correlation between small-scale turbulence-induced Reynolds stress and large-scale zonal flow production in the E×B driven hydrodynamic spectral condensation. We show that Reynolds stress is generated effectively by anisotropic vorticity structures possessing collective tilt angle. The maximum amplitude of the tilt, the Reynolds stress, and the mean zonal flow production coincide with the transition time of the velocity field, indicating a key role of turbulence-induced Reynolds stress in the condensation of the flow. The analysis of the energy transfer between turbulence and zonal flow shows coherent oscillations with π/2 phase delay, thus indicating a predator-prey-like interaction between zonal flow and turbulence.

Open Access: Yes

DOI: 10.1103/PhysRevE.90.063103

Inverse energy cascade and turbulent transport in a quasi-two-dimensional magnetized electrolyte system: An experimental study

M. Berta L. Bardóczi A. Bencze

Publication Name: Physical Review E Statistical Nonlinear and Soft Matter Physics

Publication Date: 2012-05-30

Volume: 85

Issue: 5

Page Range: Unknown

Description:

We present an experimental study of the inverse energy cascade, spectral condensation, and turbulent particle transport in an electromagnetically driven thin layer of NaCl electrolyte. The presence of the bottom friction provides an energy sink at large scales for the turbulent flow. This energy sink crucially contributes to the balance of the forcing and dissipation which makes the inverse cascade steady. The present work provides an estimation of the linear dissipation rate on an experimental basis. We also show how the dissipation rate affects the characteristic features of the velocity spectrum and the dynamics of the spectral condensation. A quantitative study of the turbulent diffusion shows a significant decrease of the radial transport during the spectral condensation process. © 2012 American Physical Society.

Open Access: Yes

DOI: 10.1103/PhysRevE.85.056315