The theory of the ion cyclotron (IC) electrostatic parametric instabilities of the inhomogeneous plasma which are driven by the inhomogeneous electric field of the fast wave (FW) in front of FW antenna is developed. It is found that the spatial inhomogeneity of the parametric IC turbulence and of the drift turbulence is at the origin of the flows which transport a large part of FW power, deposited to the pedestal plasma, to the scrape-off layer and later to the divertor mostly along field lines.
In this paper, we develop the kinetic and hydrodynamic theories of the convective mesoscale flows driven by the spatially inhomogeneous electrostatic ion cyclotron parametric microturbulence in the pedestal plasma with a sheared poloidal flow. The developed kinetic theory predicts the generation of the sheared poloidal convective flow, and of the radial compressed flow with radial flow velocity gradient. The developed hydrodynamic theory of the convective flows reveals the radial compressed convective flow as the dominant factor in the formation of the steep pedestal density profile with densi…
Transverse quasilinear relaxation of the cyclotron-Cherenkov instability in the inhomogeneous magnetic field of pulsar magnetospheres is considered. We find quasilinear states in which the kinetic cyclotron-Cherenkov instability of a beam propagating through strongly magnetized pair plasma is saturated by the force arising in the inhomogeneous field due to the conservation of the adiabatic invariant. The resulting wave intensities generally have nonpower law frequency dependence, but in a broad frequency range can be well approximated by the power law with the spectral index -2. The emergent s…
In this paper a reduced set of the partial differential wave equations valid in the conversion layer close to O-mode cutoff surface and accounting for the magnetic field 2D inhomogeneity with no restriction to an angle between the toroidal direction and the magnetic field direction is derived. An integral representation of a solution to the derived set of equation is given. For the particular case of small angle between O mode cut-off surface and X mode cut-off surface an explicit expressions for both the electric field components and the conversion coefficients are obtained and its properties…
We report the first experimental evidence of a controlled transition from the generation of periodic bursts of electromagnetic emission into continuous wave regime of a cyclotron maser formed in magnetically confined non-equilibrium plasmas. The kinetic cyclotron instability of the extraordinary wave of weakly inhomogeneous magnetized plasma is driven by the anisotropic electron population resulting from electron cyclotron plasma heating in MHD-stable minimum-B open magnetic trap.
Non-modal kinetic theory of the stability of the compressed-sheared plasma flows generated by the inhomogeneous microscale turbulence in the tokamak edge plasma
Remote sensing observations of coronal holes show that heavy ions are hotter than protons and their temperature is anisotropic. In-situ observations of fast solar wind streams provide direct evidence for turbulent Alfvén wave spectrum, left-hand polarized ion-cyclotron waves, and He$^{++}$ -- proton drift in the solar wind plasma, which can produce temperature anisotropies by resonant absorption and perpendicular heating of the ions. Furthermore, the solar wind is expected to be inhomogeneous on decreasing scales approaching the Sun. We study the heating of solar wind ions in inhomogeneous pla…
The global electrostatic mode in pair-ion plasmas is discussed for cylindric geometry and for a radially inhomogeneous equilibrium density. In the case of a Gaussian radial density profile, exact analytical eigen solutions are found in terms of the Kummer confluent hypergeometric functions. The mode is identified as a convective cell propagating in the poloidal and axial direction, having at the same time a standing wave structure in the radial direction.
Propagation and absorption of electromagnetic waves with electron cyclotron resonance (ECR) frequency are experimentally and theoretically investigated for the case of inhomogeneously magnetized plasma column with peripheral vacuum layer, when a left-hand polarized wave (LHPW) is selectively launched. The polarization reversal from the LHPW to the right-hand polarized wave is found to occur near the ECR point. As a result, it is clarified that the LHPW, which has been considered not to be absorbed at the ECR point, is absorbed near the ECR point. The phenomena can be explained by taking into a…
The plasma is generated in a low frequency glow discharge within an elongated glass tube oriented vertically. The dust particles added to the plasma are confined above the heater and form counter-rotating clouds close to the tube centre. The shape of the clouds and the velocity field of the conveying dust particles are determined. The forces acting on the particles are calculated. It is shown that convection of the dust is affected by the convective gas motion which is triggered, in turn, by thermal creep of the gas along the inhomogeneously heated walls of the tube.
A new approach to the development of extraction systems capable of forming ion beams with previously inaccessible intensity is proposed. The use of inhomogeneous accelerating field allows to improve the ion beam formation efficiency significantly. The increase of electric field magnitude is achieved by changing the shape of the electrodes only, without increasing the accelerating voltage and decreasing the interelectrode distance. The comparison is made between a new extraction system and a flat traditional one, which is the most common. The use of a new electrode geometry allows to increase t…
Parametric instabilities of the inhomogeneous near SOL tokamak plasma, driven by the coupled effect of the high harmonic fast wave and of the ion and electron temperatures gradients, and anomalous heating of the near SOL ions
Plasma Research Center, Pusan National University（釜山国立大学等离子体研究中心）；Department of Electrical Engineering, Pusan National University（釜山国立大学电气工程系）
We report on a successful test of a new method for intense ion beam formation using an extraction with inhomogeneous electric field. Its key feature is a special shape of the extraction electrodes providing a higher rate of ion acceleration. It is applicable to any ion source type and could be used to improve performance of a wide range of plasma devices. The proof of concept was carried out using a high-current electron-cyclotron resonance ion source SMIS 37. High efficiency of the new extraction and proton beam formation with a record current density of up to 1.1 A cm-2 was demonstrated.
We study the generation of parallel electric fields by virtue of propagation of ion cyclotron waves (with frequency 0.3 w_{ci}) in the plasma with a transverse density inhomogeneity. Using two-fluid, cold plasma linearised equations, we show for the first time that E_|| generation can be understood by an analytic equation that couples E_|| to the transverse electric field of the driving ion cyclotron wave. In this simplified model, the generated E_|| amplitude e.g. for plausible solar coronal parameters attains values of 90 V/m for the mass ratio m_i/m_e=262, within a time corresponding to 3 p…
Mecheri and Marsch concluded that drift currents caused by density gradients can serve as an energy source for a plasma instability, in particular for the excitation of ion-cyclotron waves in the solar corona. It is pointed out that these authors overlooked some fundamental properties of the drift motion in inhomogeneous plasmas. The calculation is repeated, taking into account the missing terms. It is shown that the diamagnetic drift, which is essential for the new physical phenomena obtained by Mecheri and Marsch, can not contribute to the flux in the continuity equation. Moreover, the part …
The expansion of hot electrons in flaring magnetic loops is crucial to understanding the dynamics of solar flares. In this paper we investigate, for the first time, the transport of hot electrons in a magnetic mirror field based on a 1-D particle-in-cell (PIC) simulation. The hot electrons with small pitch angle transport into the cold plasma, which leads to the generation of Langmuir waves in the cold plasma and ion acoustic waves in the hot plasma. The large pitch angle electrons can be confined by the magnetic mirror, resulting in the different evolution time scale between electron parallel…
Hollow toroidal rotation profiles in strongly electron heated H-mode plasmas in the ASDEX Upgrade tokamak
Max Planck Institute for Plasma Physics（马克斯·普朗克等离子体物理研究所）；Department of Applied Physics and Applied Mathematics, Columbia University（哥伦比亚大学应用物理与应用数学系）；VTT（芬兰技术研究中心VTT）
Electric field measurement in plasmas permits quantitative comparison between the experiment and the simulation in this study. An electro-optic (EO) sensor based on Pockels effect is demonstrated to measure wave electric fields in the laboratory magnetosphere of the RT-1 device with high frequency heating sources. This system gives the merits that electric field measurements can detect electrostatic waves separated clearly from wave magnetic fields, and that the sensor head is separated electrically from strong stray fields in circumference. The electromagnetic waves are excited at the double …
Microwave heating of a high-temperature plasma confined in a large-scale open magnetic trap, including all important wave effects like diffraction, absorption, dispersion and wave beam aberrations, is described for the first time within the first-principle technique based on consistent Maxwell's equations. With this purpose, the quasi-optical approach is generalized over weakly inhomogeneous gyrotrotropic media with resonant absorption and spatial dispersion, and a new form of the integral quasi-optical equation is proposed. An effective numerical technique for this equation's solution is deve…
Type III radio bursts are radio emissions associated with solar flares. They are considered to be caused by electron beams traveling from the solar corona to the solar wind. Magnetic reconnection is a possible accelerator of electron beams in the course of solar flares since it causes unstable distribution functions, and density inhomogeneities (cavities). The properties of radio emission by electron beams in an inhomogeneous environment are still poorly understood. We capture the non-linear kinetic plasma processes of generation of beam-related radio emissions in inhomogeneous plasmas by util…
A Quantum Walk Inspired Qubit Lattice Algorithm for Simulating Electromagnetic Wave Propagation and Scattering in Conservative and Dissipative Magnetized Plasmas
