Year: 2026
Type: preprint
Abstract: Spatial correlation functions of density fluctuations are measured in the Tokamak à Configuration Variable (TCV) using a dual-channel Doppler backscattering (DBS) diagnostic. In certain cases, the spatial correlation function exhibits two characteristic length scales. By analogy with nonlinear reduced simulations, the presence of two correlation lengths may be indicative of avalanche-like transport. The correlation functions obtained from DBS are compared with those from short-pulse reflectometry measurements and show reasonable agreement. Both short- and long-range correlations are measured in the same plasma geometry for different heating powers. Short-scale correlation lengths are found to be on the order of 3-5 Larmor radii, while large-scale correlations extend over approximately 5-15 Larmor radii. The correlations are found to decrease towards the very edge of electron cyclotron heated discharges, coinciding with a narrow Er well.
Source: arXiv (Cornell University)
Institutions: École Polytechnique Fédérale de Lausanne, Centre National de la Recherche Scientifique, École Polytechnique, Sorbonne Université, Institut Polytechnique de Paris, Laboratoire de Physique des Plasmas, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Cadarache, Institut de Recherche sur la Fusion par confinement Magnétique
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213223464