Lost electron energy distribution of electron cyclotron resonance ion sources.

To ensure further progress in the development of electron cyclotron resonance ion sources (ECRISs), deeper understanding of the underlying physics is required. The electron energy distribution (EED), which is crucial for the performance of an ECRIS, still remains obscure. The present paper focuses on the details of a well-developed technique of measuring the EED of electrons escaping axially from the magnetically confined plasma of an ECRIS.

Gasdynamic electron cyclotron ion sources: Basic physics, applications, and diagnostic techniques.

The gasdynamic electron cyclotron resonance (ECR) ion source is a type of the device in which the ionization efficiency is achieved primarily due to a high plasma density. Because of a high particle collision rate, the confinement is determined by a gasdynamic plasma outflow from a magnetic trap. Due to high efficiency of resonant heating, electrons gain energy significantly higher than that in inductively or capacitively coupled plasmas.

Study of gasdynamic electron cyclotron resonance plasma vacuum ultraviolet emission to optimize negative hydrogen ion production efficiency.

Negative hydrogen ion sources are used as injectors into accelerators and drive the neutral beam heating in ITER. Certain processes in low-temperature hydrogen plasmas are accompanied by the emission of vacuum ultraviolet (VUV) emission. Studying the VUV radiation, therefore, provides volumetric rates of plasma-chemical processes and plasma parameters.

A powerful pulsed "point-like" neutron source based on the high-current ECR ion source.

The paper presents recent results of a "pointlike" neutron source development based on a D-D fusion in a D-loaded target caused by its bombardment with a sharply focused deuterium ion beam. These developments are undergoing at the Institute of Applied Physics of Russian Academy of Sciences in order to study a possibility to create an effective and compact device for fast-neutron radiography. The last experiments with a beam produced by a gasdynamic high-current ECR ion source and its focusing with a magnetic lens demonstrated that 60 mA of deuterium ions may be constricted to a transversal size of ∼1 mm at the focal plane.

Measurements of the energy distribution of electrons lost from the minimum B-field-The effect of instabilities and two-frequency heating.

Further progress in the development of electron cyclotron resonance (ECR) ion sources (ECRISs) requires deeper understanding of the underlying physics. One of the topics that remains obscure, though being crucial for the performance of the ECRIS, is the electron energy distribution (EED). A well-developed technique of measuring the EED of electrons escaping axially from the magnetically confined plasma of an ECRIS was used for the study of the EED in an unstable mode of plasma confinement, i.

Status of the gasdynamic ion source for multipurpose operation (GISMO) development at IAP RAS.

A new experimental facility named GISMO (Gasdynamic Ion Source for Multipurpose Operation) was constructed at the IAP RAS to continue investigations in the field of gasdynamic ion sources. The source utilizes 28 GHz/10 kW gyrotron radiation for heating magnetically confined plasma. Magnetic field configuration provided by a fully permanent magnet system is much like a simple mirror trap.

The biased disc of an electron cyclotron resonance ion source as a probe of instability-induced electron and ion losses.

Electron Cyclotron Resonance Ion Source (ECRIS) plasmas are prone to kinetic instabilities resulting in loss of electron and ion confinement. It is demonstrated that the biased disk of an ECRIS can be used as a probe to quantify such instability-induced electron and ion losses occurring in less than 10 µs. The qualitative interpretation of the data is supported by the measurement of the energy spread of the extracted ion beams implying a transient plasma potential >1.

Wide-aperture dense plasma fluxes production based on ECR discharge in a single solenoid magnetic field.

Results of experimental investigation of the ECR discharge in a single coil magnetic field as an alternative to rf and helicon discharges for wide-aperture dense plasma fluxes production are presented. A possibility of obtaining wide-aperture high density hydrogen plasma fluxes with homogeneous transverse distribution was demonstrated in such a system. The prospects of using this system for obtaining high current ion beams are discussed.

Plasma diagnostic tools for ECR ion sources-What can we learn from these experiments for the next generation sources.

The order-of-magnitude performance leaps of ECR ion sources over the past decades result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency, and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves, significant effort has been directed into the development of their plasma diagnostic tools. We review the recent results of Electron Cyclotron Resonance Ion Source (ECRIS) plasma diagnostics highlighting a number of selected examples of plasma density, electron energy distribution, and ion confinement time measurements, obtained mostly with the second-generation sources operating at frequencies from 10 to 18 GHz.

Prospect for a 60 GHz multicharged ECR ion source.

The conceptual design of a fourth generation hybrid electron cyclotron resonance (ECR) ion source operated at 60 GHz is proposed. The axial magnetic mirror is generated with a set of three NbSn coils, while the hexapole is made with room temperature (RT) copper coils. The motivations for such a hybrid development are to study further the ECR plasma physics and the intense multicharged ion beams' production and transport at a time when a superconducting (SC) hexapole appears unrealistic at 60 GHz.

Observation of Poincaré-Andronov-Hopf Bifurcation in Cyclotron Maser Emission from a Magnetic Plasma Trap.

We report the first experimental evidence of a controlled transition from the generation of periodic bursts of electromagnetic radiation into the continuous-wave regime of a cyclotron maser formed in magnetically confined nonequilibrium plasma. 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 a MHD-stable minimum-B open magnetic trap.

Study of hydrogen ECR plasma in a simple mirror magnetic trap heated by 75 GHz pulsed gyrotron radiation.

Plasma of electron cyclotron resonance (ECR) discharge sustained by millimeter wave radiation is widely used for production of ion beams of different kind. The main trend in ECR ion sources development nowadays is an increase of frequency and power of microwave heating. The most advanced systems use gyrotrons in 24-60 GHz frequency range.

The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source.

The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success.

Cyclotron instability in the afterglow mode of minimum-B ECRIS.

It was shown recently that cyclotron instability in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source (ECRIS) causes perturbation of the extracted ion current and generation of strong bursts of bremsstrahlung emission, which limit the performance of the ion source. The present work is devoted to the dynamic regimes of plasma instability in ECRIS operated in pulsed mode. Instability develops in decaying plasma shortly after heating microwaves are switched off and manifests itself in the form of powerful pulses of electromagnetic emission associated with precipitation of high energy electrons.

New progress of high current gasdynamic ion source (invited).

The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)-the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller's ECRIS confinement, i.e.

First experiments with gasdynamic ion source in CW mode.

A new type of ECR ion source-a gasdynamic ECR ion source-has been recently developed at the Institute of Applied Physics. The main advantages of such device are extremely high ion beam current with a current density up to 600-700 emA/cm(2) in combination with low emittance, i.e.

Limitation of the ECRIS performance by kinetic plasma instabilities (invited).

Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropic electron velocity distribution. The instabilities are associated with strong microwave emission and periodic bursts of energetic electrons escaping the magnetic confinement. The instabilities explain the periodic ms-scale oscillation of the extracted beam current observed with several high performance ECRISs and restrict the parameter space available for the optimization of extracted beam currents of highly charged ions.

Kinetic instabilities in pulsed operation mode of a 14 GHz electron cyclotron resonance ion source.

The occurrence of kinetic plasma instabilities is studied in pulsed operation mode of a 14 GHz A-electron cyclotron resonance type electron cyclotron resonance ion source. It is shown that the temporal delay between the plasma breakdown and the appearance of the instabilities is on the order of 10-100 ms. The most important parameters affecting the delay are magnetic field strength and neutral gas pressure.

Neutron generator for BNCT based on high current ECR ion source with gyrotron plasma heating.

BNCT development nowadays is constrained by a progress in neutron sources design. Creation of a cheap and compact intense neutron source would significantly simplify trial treatments avoiding use of expensive and complicated nuclear reactors and accelerators. D-D or D-T neutron generator is one of alternative types of such sources for.

Limitations of electron cyclotron resonance ion source performances set by kinetic plasma instabilities.

Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropy of the electron energy distribution function stemming from the resonant nature of the electron heating process. Electron cyclotron plasma instabilities are related to non-linear interaction between plasma waves and energetic electrons resulting to strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents observed in several laboratories. It is demonstrated with a minimum-B 14 GHz ECRIS operating on helium, oxygen, and argon plasmas that kinetic instabilities restrict the parameter space available for the optimization of high charge state ion currents.

High current proton beams production at Simple Mirror Ion Source 37.

This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition.

Emittance of short-pulsed high-current ion beams formed from the plasma of the electron cyclotron resonance discharge sustained by high-power millimeter-wave gyrotron radiation.

We present experimental results on measuring the emittance of short-pulsed (≤100 μs) high-current (80-100 mA) ion beams of heavy gases (Nitrogen, Argon) formed from a dense plasma of an ECR source of multiply charged ions (MCI) with quasi-gas-dynamic mode of plasma confinement in a magnetic trap of simple mirror configuration. The discharge was created by a high-power (90 kW) pulsed radiation of a 37.5-GHz gyrotron.

Optimization of gas utilization efficiency for short-pulsed electron cyclotron resonance ion source.

Numerical analysis of (6)He atoms utilizing efficiency in the ion source with powerful gyrotron heating is performed in present work using zero-dimensional balanced model of ECR discharge in a magnetic trap. Two ways of creation of ion source with high gas utilization efficiency (up to 60%-90%) are suggested.

Influence of the shear flow on electron cyclotron resonance plasma confinement in an axisymmetric magnetic mirror trap of the electron cyclotron resonance ion source.

Influence of shear flows of the dense plasma created under conditions of the electron cyclotron resonance (ECR) gas breakdown on the plasma confinement in the axisymmetric mirror trap ("vortex" confinement) was studied experimentally and theoretically. A limiter with bias potential was set inside the mirror trap for plasma rotation. The limiter construction and the optimal value of the potential were chosen according to the results of the preliminary theoretical analysis.

Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions.

Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method.