Related papers: On the density limit in the helicon plasma sources
Radio-frequency discharges are performed in low magnetic fields (0-10 mT) using three types of helicon-wave exciting antennas with the azimuthal mode number of $|m|$ = 1. The most pronounced peak of plasma density is generated in the case…
A crucial problem concerning a large variety of fusion devices is that the confinement due to an external magnetic field is lost above a critical density, while a widely accepted first principles explanation of such a fact is apparently…
The density limit of lower hybrid current drive (LHCD) is scaled by coupling the saturation process of parametric decay instability induced by LH waves in the scrape off layer (SOL) plasma to the propagation of waves. It is shown that the…
The ionization efficiency of helicon plasma discharge is explored by changing the low axial magnetic field gradients near the helicon antenna. The highest plasma density is found for a most possible diverging field near the antenna by…
A limit for the edge density, ruled by radiation losses from light impurities, is established by a minimal cylindrical magneto-thermal equilibrium model. For ohmic tokamak and reversed field pinch the limit scales linearly with the plasma…
Helicon plasmas are being considered as plasma sources for wakefield accelerators, subject to strict density requirements. We present various mechanisms to increase axial density homogeneity in a helicon plasma for implementation in such an…
Hairpin probes measure electron density in plasmas where other techniques are unsuitable. Previous hairpins were constructed as a quarter-wave resonant structure typically made from a folded piece of wire. The present work conducts the…
Fusion research on magnetic confinement is confronted with a severe problem concerning the electron densities ne to be used in fusion devices. Indeed, high densities are mandatory for obtaining large efficiencies, whereas it is empirically…
Waves propagating along a converging-diverging rf magnetoplasma having the characteristics of a bounded m=0 helicon mode are reported and characterised. The discharge features a 30 cm separation between the region of radiofrequency energy…
Previously developed method for finding asymptotic solutions of Vlasov equations using two-dimensional (in coordinate x and time t) Laplace transform is applied to low-collision electron-ion plasmas. Taking into account Coulomb collisions…
The radial characteristics of plasma potential and density around an insulating disc obstacle, placed inside a partially magnetized plasma flow created in cylindrical chamber by hot cathode filament are presented. In the absence of…
Helicon waves satisfying the normal wave-particle cyclotron resonance are observed to limit the growth and maximum energy of relativistic electrons (REs) in low-density Ohmic DIII-D tokamak plasmas. Following the application of helicon…
We investigate the low density limit of the Homogeneous Electron system, often called the {\it Strictly Correlated} regime. We begin with a systematic presentation of the expansion around infinite $r_S$, based on the first quantized…
The density limit is a mysterious barrier to magnetic confinement nuclear fusion, and is still an unresolved issue. In this paper, we will present the experimental results of the density limit and core-localized kinetic MHD instabilities on…
IShTAR (Ion cyclotron Sheath Test ARrangement) is a dedicated test facility to investigate the interaction of ICRF wave and plasma at the Max-Planck Institute for Plasma Physics in Garching, Germany. Plasma is provided by a plasma source…
Radio-frequency (RF) driven helicon plasma sources can produce relatively high-density plasmas (n > 10^19 m-3) at relatively moderate powers (< 2 kW) in argon. However, to produce similar high-density plasmas for fusion relevant gases such…
We show that in a neutral magnetized plasma there exist microscopic oscillatory modes, with wavelengths of the order of magnitude of the mean interparticle distance, which become unstable when the electron density exceeds a limit…
Large volume helicon plasma sources are of particular interest for large scale semiconductor processing, high power plasma propulsion and recently plasma-material interaction under fusion conditions. This work is devoted to studying the…
Helicon plasma sources play a central role in applications ranging from material treatment to space propulsion and fusion, yet the physical processes governing their ignition, transient ionization, and mode evolution remain incompletely…
Measurement of radial density profile in both the source and expansion chambers of a helicon plasma device have revealed that it is always centrally peaked in the source chamber, whereas in the expansion chamber near the diverging magnetic…