Yaglom law for electrostatic turbulence in laboratory magnetized plasmas

¹  Dipartimento di Fisica, Università della Calabria - Ponte P. Bucci Cubo 31C, 87036 Rende (CS), Italy
²  LICRYL/INFM Regional Laboratory - Ponte P. Bucci Cubo 33B, 87036 Rende (CS), Italy
³  Consorzio RFX, Associazione Euratom-ENEA sulla Fusione - Corso Stati Uniti 4, 35127 Padova, Italy

Corresponding author: lepreti@fis.unical.it

Received: 31 October 2008
Accepted: 27 March 2009

Abstract

It has recently been shown that a Yaglom law for electrostatic turbulence, that is, a relation for the third-order mixed moment involving the particle number density as a passive scalar and the EB drift velocity, can be deduced from a simple model of electrostatic fluctuations, which describes bursty turbulence in plasmas. In this letter, the existence of the Yaglom law for electrostatic turbulence in laboratory magnetized plasmas is reported for the first time. Using measurements of intermittent transport at the edge of the RFX-mod reversed field pinch plasma device, we found that the above scaling relation is nicely verified at intermediate scales of few centimeters. In this range of scales, that unambiguously represents the inertial range of electrostatic turbulence, we also analyze the intermittency properties of electrostatic turbulence by measuring anomalous scaling exponents of density and velocity structure functions.