Reducing systematic errors in time-frequency resolved mode number analysis

  title={Reducing systematic errors in time-frequency resolved mode number analysis},
  author={Lajos Horv'ath and Peter Zs. Poloskei and Gergely Papp and Marc Maraschek and K. H. Schuhbeck and G I Pokol},
  journal={Plasma Physics and Controlled Fusion},
The present paper describes the effect of magnetic pick-up coil transfer functions on mode number analysis in magnetically confined fusion plasmas. Magnetic probes mounted inside the vacuum chamber are widely used to characterize the mode structure of magnetohydrodynamic modes, as, due to their relative simplicity and compact nature, several coils can be distributed over the vessel. Phase differences between the transfer functions of different magnetic pick-up coils lead to systematic errors in… 

Toroidal mode number determination of ELM associated phenomena on ASDEX Upgrade

In highly confined tokamak plasmas periodically appearing edge localized modes (ELMs) are accompanied by mode-like magnetohydrodynamic (MHD) activities with defined toroidal mode numbers. Here the

Investigation of the eddy current effect on the high frequency response of the Mirnov probe on J-TEXT.

This paper investigates the high frequency response of the Mirnov probe based on a test platform, which is capable of generating a uniform AC magnetic field within the frequency range of 1-300 kHz.

Fast changes in the mode structure of chirping energetic particle driven modes

Super-thermal energetic particles (EP) in tokamak plasmas can excite various instabilities which can lead to an enhanced transport of fast particles. These instabilities constitute a nonlinear system

Experimental investigation of the radial structure of energetic particle driven modes

Alfvén eigenmodes (AEs) and energetic particle modes (EPMs) are often excited by energetic particles (EPs) in tokamak plasmas. One of the main open questions concerning EP driven instabilities is the

Pedestal structure and inter-ELM evolution for different main ion species in ASDEX Upgrade

In tokamak plasmas with different main ion species, a change in confinement occurs, known as the isotope effect. Experiments comparing hydrogen (H), deuterium (D), and helium (4He) plasmas have been

Review: Turbulence dynamics during the pedestal evolution between edge localized modes in magnetic fusion devices

Fusion performance has been shown to be related to the H-mode pedestal structure. The pedestal is associated with steep gradients that are the source of free energy for microinstabilities. A variety

Spatiotemporal analysis of the runaway distribution function from synchrotron images in an ASDEX Upgrade disruption

Synchrotron radiation images from runaway electrons (REs) in an ASDEX Upgrade discharge disrupted by argon injection are analysed using the synchrotron diagnostic tool Soft and coupled fluid-kinetic

The effects of the misalignment of Mirnov coils in mode analysis based on the phase detection method

Mirnov coils (MCs) are used to identify the toroidal and poloidal mode number of tearing mode instabilities in the KSTAR tokamak. The mode number is analyzed by accumulating the phase of MC signals...

Observation of toroidal Alfvén eigenmodes during minor disruptions in ohmic plasmas

Toroidal Alfven eigenmodes (TAEs) excited in purely ohmically heated plasmas without any auxiliary heating have been identified for the first time in the SUNIST spherical tokamak. The TAE modes are



A multichannel magnetic probe system for analysing magnetic fluctuations in helical axis plasmas.

The need to understand the structure of magnetic fluctuations in H-1NF heliac plasmas has motivated the installation of a sixteen former, tri-axis helical magnetic probe Mirnov array (HMA), which complements two existing poloidal Mirnov arrays by providing polarisation information, higher frequency response, and improved toroidal resolution.

Fast magnetic fluctuation diagnostics for Alfvén eigenmode and magnetohydrodynamics studies at the Joint European Torus

Alfven eigenmodes and other magnetohydrodynamic phenomena have been studied in tokamak plasmas at the Joint European Torus (JET) using a new eight-channel, 4 s, 1 MHz, 12-bit data acquisition system

Changes in the radial structure of EPMs during the chirping phase taking the uncertainties of the time-frequency transforms into account

Mode amplitude and uncertainties In order to reach our goal the soft X-ray (SXR) diagnostics of ASDEX Upgrade was used. We analyzed the signals from six line of sights (LOS) of camera J measuring the

Application of a bandpower correlation method to the statistical analysis of MHD bursts in quiescent Wendelstein-7 AS stellarator plasmas

This paper presents the analysis of Mirnov coil data from pure electron-cyclotron resonance heated Wendelstein-7 AS discharges with transient magnetohydrodynamical (MHD) mode activity in otherwise

Characterization of saturated MHD instabilities through 2D electron temperature profile reconstruction from 1D ECE measurements

A new method for the reconstruction of two-dimensional (2D) electron temperature profiles in the presence of saturated magneto-hydro-dynamic (MHD) modes from the one-dimensional (1D) electron

The non-linear evolution of edge localized modes

Edge localized modes (ELMs) are instabilities in the edge of tokamak plasmas in the high confinement regime (H-mode). Without them the edge transport in ordinary H-mode plasmas is too low to

MHD stability limits in the TCV tokamak

Magnetohydrodynamic (MHD) instabilities can limit the performance and degrade the confinement of tokamak plasmas. The Tokamak a Configuration Variable (TCV), unique for its capability to produce a

Fast-ion transport induced by Alfvén eigenmodes in the ASDEX Upgrade tokamak

A comprehensive suite of diagnostics has allowed detailed measurements of the Alfvén eigenmode (AE) spatial structure and subsequent fast-ion transport in the ASDEX Upgrade (AUG) tokamak [1].

Analysis of Alfvén eigenmodes in stellarators using non-evenly spaced probes

Eigenmodes play an important role in the dynamics of spatially extended systems. Using arrays of probes, it is possible to measure the spatial structure of experimentally observed fluctuations. But

Continuous linear time-frequency transforms in the analysis of fusion plasma transients

This paper concentrates on continuous transforms that are time-shift invariant, thus ideal for the analysis of transient signals (for example: chirps, sawtooth, ELMs, EPMs, etc.).