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Plasma source ion implantation (PSII) with metal plasma results in a qualitatively different kind of surface modification than with gaseous plasma due to the condensable nature of the metal plasma, and a new, PSII‐related technique can be defined: metal plasma immersion ion implantation and deposition (MPI). Tailored, high‐quality films of any solid metal, metal alloy, or carbon (amorphous diamond) can be formed by MPI using filtered vacuum arc plasma sources, and compounds such as oxides or nitrides can be formed by adding a gas flow to the deposition. Here we describe the plasma formation at cathode spots, macroparticle filtering of the vacuum arc plasma by magnetic ducts, the underlying physics of MPI, and present some examples of MPI applications.

Measurements have been made of the transport of beams produced by the high current ion source, MEVVA, and of the injection of these beams into the GSI heavy ion RFQ linac. This configuration has provided initial tests of the MEVVA ion source in an injector environment, and of the RFQ with uranium as the accelerated species. Beam currents of 78 mA of titanium and 19 mA of uranium, at an extraction voltage of 40 kV, have been transported through a 4.7 m long beam transport channel, and up to 40 mA of uranium has been transported through a single-gap accelerating column at a voltage of about 150 kV. A current of up to 5 mA of U 3+ has been measured at the exit detector of the RFQ.

A new kind of ion source has been developed in which a MEtal Vapor Vacuum Arc (MEVVA) is used to produce the plasma from which the ion beam is extracted. The novel and exciting feture of this source is the very high metal ion beam current attainable. A total ion beam current of over 1 Ae has been extracted from the embodiment of the concept that we are presently using, and this is not a limit of the method. The source was developed to upgrade the uranium ion beam intensity of the Bevatron, LBL's heavy ion synchrotron, for basic nuclear physics research. Other important applications include its use within the Heavy Ion Fusion research effort; for ion implantation; and for other basic research uses. In this paper the source is described briefly, its performance outlined, and its potential and limitations for a variety of applications is discussed.

We consider the charge state distribution of ions produced in the metal vapor vacuum arc plasma discharge. A new kind of high current metal ion source in which the ion beam is extracted from a metal vapor vacuum arc plasma has been used to obtain the spectra of multiply charged ions produced within the cathode spots. The cathode materials used and the species reported on here are: C, Mg, Al, Si, Ti, Cr, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Rh, Pd, Ag, In, Sn, Gd, Ho, Ta, W, Pt, Au, Pb, Th, and U; the arc current was 200 A for all measurements. Charge state spectra were measured using a time‐of‐flight method. In this paper we report on the measured charge state distributions and arc voltages and compare the distributions with the predictions of a theory in which ionization occurs in the cathode spots via stepwise ionization by electron impact.

Beams of metallic ion species can be produced by the ECR (electron cyclotron resonance) ion source and by the MEVVA (metal vapor vacuum arc) ion source. Although the ECR source is fundamentally a gaseous ion source, metal ion beams can be produced by introducing metallic feed material into the plasma discharge using a number of techniques. The ion charge states can be very high, which is a significant advantage to most applications. The MEVVA ion source, on the other hand, is specifically a metal ion source. It has produced metallic ion beams from virtually all the solid metallic elements at a current of typically hundreds of milliamperes; the ions produced are in general multiply ionized, but not as highly stripped as those generated in the ECR source. Although the MEVVA source at present operates in a pulsed mode with a low duty cycle ( ≤ 1%), work is in progress to increase the duty cycle significantly. In this paper the operation and performance of the LBL ECR and MEVVA ion sources, with respect to metal ion generation, are described.

Implantation of uranium ions into silicon to a dose of 6 × 10 16 atoms/cm 2 , with a maximum concentration of 6 × 10 21 atoms/cm 3 , has been carried out at an ion mean energy of 157 keV. The implanted uranium content was measured by Rutherford backscattering and confirmed by a measurement of the alpha-particle activity of the buried uranium layer. The range and straggling of the uranium implant, and sputtering of the silicon target by uranium, were measured and are compared with theoretical estimates.

Transport of high current beams of metal ions through the injector beam line of the heavy ion linear accelerator, UNILAC, has been demonstrated using the MEVVA high current metal ion source. Improved operation of the MEVVA source has been achieved in various ways, including shot-to-shot reproducibility of the beam pulse, beam noise, pulse shape, and absence of “missing” pulses. The source was first tested on a high current test stand beam line, and then moved over to regularly used UNILAC injector terminal. Flat and reproducible titanium ion beam pulses were efficiently transported through the system from the ion source to the Wideroe preaccelerator entrance. A beam current of 20 mA (pulse current) of titanium (all charge states, q = 1, 2, 3) was accelerated to an energy of 280 Q keV through the single-gap accelerating structure, and a current of over 5 mA of Ti 2+ was measured at the Wideroe entrance 13 m downstream.

The metal vapor vacuum arc is a prolific generator of highly ionized metal plasma in which the ions are in general multiply stripped. We have utilized this plasma production mechanism to make a high current metal ion source. The metal vapor vacuum arc ion source is thus a laboratory tool for providing high quality, high current beams of a wide range of metal ion species. Charge state spectra have been measured using a time-of-flight diagnostic. In this paper we review the ion source development program, describe the various embodiments of the concept that have been made, and summarize those experimental results relating to the ion charge states that can be produced.

Finite Element Study of the Nevis Bluff (New Zealand) Rock Slope Failure In June 1975, part of the Nevis Bluff rock slope failed along State Highway 6 in the South Island of New Zealand. The slope is near the bottom of the Kawarau River valley, which has been deeply entrenched in chlorite schist rocks. The detailed geology of the slope, and the mechanical properties of the rocks comprising the slope are described. For the purposes of finite element modelling, the schist was assumed to be a transversely isotropic material with four independent deformability parameters. A two dimensional finite element program was used to establish the regional state of stress, the results from which were then used in a larger scale model of the rock slope. The results of finite element analyses suggested that slope failure occurred by flexural toppling, where continuous columns broke in flexure as they slid along schistosity surfaces. Flexural cracking was then responsible for propagating the plane along which sliding occurred. When the shear strength available along this plane was exceeded by shear stresses, the slope failed.

The maximum ion current that can be extracted as a high-energy beam from a metal-vapor vacuum-arc ion source is considered. Results are presented of measurements of the plasma ion current in the metal-vapor vacuum-arc II (MEVVA II) ion source. It is shown that this source is an efficient generator of metal ions, an intense flux of which is efficiently transported to the beam extractor. The maximum metal-ion current that is available for extraction at the extractor location is 5 percent of the arc current. The limitation to the intensity of the metal-ion beam that can be produced by this kind of ion source is found to be in the extractor design.

An ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ions are extracted. Beams of a variety of ions have been produced, ranging from lithium up to uranium. At an extraction voltage of 25 kV we've measured an ion beam current of over 1 Ampere, with over 550 ema of the beam in an emittance of 0.07 ? cm. mradians (normalized). The ion charge state distribution varies with cathode material and with arc power; for uranium a typical distribution is peaked at U5+, with up to 40% of the beam current in this charge state.

A time‐of‐flight diagnostic for analysis of relatively low‐energy ion beams is described. The system incorporates several novel features which improve its performance in a number of ways. The technique is simple and can provide an alternative to magnetic analysis of ion beams for the determination of ion charge state and beam composition.

We have carried out an experimental investigation of the charge state distribution of ions produced in the vacuum arc plasma for the case when the cathode is a compound or alloy. The plasma was generated in a metal vapor vacuum arc ion source, and the charge state spectra were measured using a time‐of‐flight method. We have compared these spectra to the spectra obtained from cathodes of the constituent elements. The cathode materials used and reported on here were the following groups: SiC/Si/C [i.e., we have compared the spectra obtained using a cathode of silicon carbide with the spectra obtained using (a) a silicon cathode and (b) a carbon cathode], TiC/TiN/TiO2/Ti/C, WC/W/C, (UC‐ZrC)/UN/U/Zr/C, brass/Cu/Zn, and stainless steel/Fe/Cr/Ni. The arc current employed throughout was approximately 100 A. We find that the charge state distributions change depending on the elemental composition of the alloy or compound of which the cathode is fabricated.

A relatively simple and inexpensive device is described which can be used to provide a highly homogeneous magnetic field in a solenoid when the solenoid windings are inadequate. Design considerations and experiments measurements are presented. A field straightness of approximately 10−4 rad has been achieved.

The charge-state distribution of ions generated in the metal vapor vacuum arc under a wide range of experimental conditions was measured. The experiments were carried out using an ion source in which the metal vapor vacuum arc is used as the method of plasma production and by which a high-quality, high-current beam of metal ions is produced. Charge-state spectra were measured using a time-of-flight diagnostic; arc voltages were also measured. Parameters that were varied include cathode material, arc current, axial magnetic field strength, neutral gas pressure, and arc geometry. >

A high‐current ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ion beam is extracted. An ion beam current of up to about 1 A has been measured at an extraction voltage of 25 kV for a range of metallic species spanning the periodic table from lithium to uranium. Multiply ionized charge states are seen up to as high as Q=6+ in the case of uranium. In the metal vapor vacuum arc, regions of intense current concentration are formed at the cathode, and it is at these regions, the cathode spots, that the cathode material is vaporized and ionized to form a dense, quasi‐neutral plasma which plumes away from the cathode surface. The plasma plume is caused to impinge upon a set of extractor grids, and the ion beam is extracted from the streaming metal plasma. A preliminary survey of the performance of the source has been made. We describe here the principle of operation of the source, the source design, and the results of those measurements that we have made to date.

Microwave power resonant to the local electron cyclotron frequency has been coupled into the plasma discharge chamber of a hot‐cathode PIG (Philips or Penning Ionization Gauge) ion source. The extracted ion beam was monitored for changes in characteristics of the beam with and without application of the microwave power. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and this technique may thus find application in situations where beam quiescence is important.

We have investigated the effect of applying microwave power at the electron cyclotron frequency on the characteristics of the ion beam extracted from a hotcathode PIG ion source. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and it is possible that the technique may find application in situations where beam quiescence is important.

An ion source utilizing a cathode and anode for producing an electric arc therebetween. The arc is sufficient to vaporize a portion of the cathode to form a plasma. The plasma leaves the generation region and expands through another regon. The density profile of the plasma may be flattened using a magnetic field formed within a vacuum chamber. Ions are extracted from the plasma to produce a high current broad on beam.

This project will increase the uranium output of the Bevalac heavy-ion facility from the currently available 107 to 5×107 ions/pulse, allowing accurate Lamb shift measurements to be made in U90+ and U91+ with important applications to the testing of quantum electrodynamics and the development of an x-ray laser. The injected beam intensity will be increased to make better use of the 10emA output space-charge limit of the Wideroe linac. Components will include a new high current MEtal Vapor Vacuum Arc (MEVVA) ion source1 along with an improved high current, high voltage Cockcroft-Walton power supply to handle the increased beam current. The Low Energy Beam Transport (LEBT) line will be upgraded with additional focusing to manage the increased space-charge forces and with an improved vacuum to reduce charge exchange losses. Finally, the phase matching between the 23MHz Wideroe linac and the 70MHz Alvarez linac will be improved by the addition of the appropriate buncher cavities. Physics design is underway and detailed engineering is scheduled to begin in October 1985, with installation slated for the 1986 summer shutdown.

A small, simple ion source for the production of high brightness beams of metal ions is described. A metal vapor vacuum arc discharge is used to establish the high density plasma from which the ion beam is extracted. The source is finger sized, and can produce pulsed metal ion beams with current up to the 10‐mA range.

The stable confinement of a fully ionized, high-beta plasma in a toroidal bicusp (Tormac) is discussed. The bicusp geometry is described along with ''shaker'' heating by magnetoacoustic waves propagating orthogonal to the internal toroidal magnetic field. (MOW)

We have used high-dose metal ion implantation to ‘fine tune’ the composition of Y-Ba- Cu-O thin films. The films were prepared by either of two rf sputtering systems. One system uses three modified Varian S-guns capable of sputtering various metal powder targets; the other uses reactive rf magnetron sputtering from a single mixed-oxide stoichiometric solid target. Film thickness was typically in the range 2000–5000 A. Substrates of magnesium oxide, zirconia-buffered silicon, and strontium titanate have been used. Ion implantation was carried out using a metal vapor vacuum arc (MEVVA) high current metal ion source. Beam energy was 100–200 keV, average beam current about 1 mA, and dose up to about 1017 ions/cm2. Samples were annealed at 800 – 900°C in wet oxygen. Film composition was determined using Rutherford Backscattering Spectrometry (RBS), and the resistivity versus temperature curves were obtained using a four-point probe method. We find that the zero-resistance temperature can be greatly increased after implantation and reannealing, and that the ion beam modification technique described here provides a powerful means for optimizing the thin film superconducting properties.

We have utilized plasma immersion ion implantation (PIII) to demonstrate effective gettering of metallic impurities in silicon wafers. Metallic impurities such as Ni, Cu or Au were intentionally diffused into Si as marker impurities. The Ar or Ne atoms were ionized in an electron cyclotron resonance (ECR) plasma chamber. The ions were accelerated by a negative voltage applied to the wafer and implanted into the wafer. The as-implanted saturation dose can be as high as 5×1016cm−2. After an annealing step at 1000°C for 1 hour in a N2 ambient, the retained doses and the amount of gettered impurities were measured with Rutherford backscattering spectrometry (RBS). With a retained Ar dose in 1015cm−2 range after annealing, the gettered Ni, Cu and Au were 3.0×1014cm−2, 3.0×1014cm−2 and 4.4×1013cm−2 respectively.

We have developed an ion source which can produce high current beams of metal ions. The source uses a metal vapor vacuum arc discharge as the plasma medium from which the ions are extracted, so we have called this source the MEVVA ion source. The metal plasma is created simply and efficiently and no carrier gas is required. Beams have been produced from metallic elements spanning the periodic table from lithium through uranium, at extraction voltages from 10 to 60 kV and with beam currents as high as 1.1 Amperes (electrical current in all charge states).In this paper a brief description of the source is given and its possible application as an ion source for heavy ion fusion is considered. Beams such as C+ (≥99% of the beam in this species and charge state), Cr2+ (80%), and Ta3+,4+,5+ (mixed charge states) have been produced. Beam emittance measurements and ways of increasing the source brightness are discussed.

A relatively simple and inexpensive device is described which can be used to provide a highly homogeneous solenoidal magnetic field when the solenoid windings are inadequate. Design considerations and experimental measurements are presented. A field straightness of approximately 10{sup -4} radians has been achieved.

A time-of-flight diagnostic for analysis of relatively low energy ion beams is described. The system incorporates several novel features which improve its performance in a number of ways. The technique is simple and can provide an alternative to magnetic analysis of ion beams for the determination of ion charge state and beam composition.

A current-free magnetized plasma with independently variable density and electron temperature has been produced and studied. The plasma, which may be either steady state or pulsed, is generated at one end of a 1.5-m-long vacuum system by a 10 GHz microwave discharge at electron gyroresonance in a d.c. magnetic field. In the main body of the plasma the magnetic field can be varied from 1 to 10 kG and plasma densities 5*108

Ion charge state distributions of vacuum arc ion sources are correlated to the arc operating voltage. An enhancement of ion charge state via an increase of the arc voltage can be achieved utilizing the transient processes that accompany an arc current spike. A current spike of 100–1000 A and several microseconds width was produced on top of the main arc current pulse (100 A, 250 μs). The ion charge state distribution was measured by charge-to-mass spectrometry. The measured charge state distributions were used as input data to the plasma model of partial local Saha equilibrium, giving the time-dependent electron temperature of the plasma at the freezing zone near the cathode spot.

High temperature superconducting composite thin films on Ag substrates were prepared by cathodic arc deposition of alloy precursors. The deposition technique employed a cathode comprised of a precursor alloy for the vacuum arc plasma source. The precursor alloy was prepared by multiple arc-melting of mixed metallic constituents of the high-temperature superconducting material Bi2Sr2CaCu2Oy (Bi2212) and 50 wt.% of Ag. The presence of silver in the precursor alloy film was expected to allow accommodation of the lattice and thermal expansion mismatch between the oxidized film and the silver substrate. The as-deposited film could be formed to practically any desirable shape before being subjected to heat treatments. Following deposition, controlled oxidation of the precursor alloy thin film on the Ag substrate was performed to produce the superconducting composite on the silver substrate. After the heat treatment, the composite film consisted of Bi2212 highly c-axis oriented normal to the Ag substrate.

Metal implantation provides a powerful tool for the formation of non-equilibrium alloy layers for a wide variety of basic and applied materials applications, but the technique is fundamentally limited in two important ways: (i) the implanted species concentration is limited by sputtering of the modified layer by the incident ion beam itself, and the sputter-limited retained dose is often disappointingly low; (ii) the thickness of the modified layer is limited by the maximum ion energy available, and for practical reasons (implanter voltage) the layer thickness is often just a few hundred angstroms. We describe here a metal-plasma-immersion-based method for synthesizing non-equilibrium alloy layers of arbitrarily high dopant concentration and of arbitrary thickness. By repetitively pulse biasing the substrate to high negative voltage while it is immersed in the metal plasma from a vacuum arc plasma gun, a layer can be synthesized that is atomically mixed into the substrate with an interface width determined by the early-time bias voltage and with a thickness determined by the overall duration of the process. The species is that of the vacuum arc cathode material, which for this purpose can be a mixture of the substrate metal and the wanted dopant metal. We have used the method to form a high concentration Ta layer on the copper rails of an electromagnetic rail gun, with total surface area treated about 3000 cm2; the Ta depth profile was flat at about 50 at.% Ta in Cu to a depth of about 1000 A.

Summary form only given. A vacuum arc ion source based metal ion implantation facility has been established at Dokuz Eylul University, Izmir, Turkey and a surface modification research and development program is underway. The system is similar to the one in Lawrence Berkeley Laboratory which was first built and developed by Brown et al. The broad-beam ion source is repetitively pulsed at rates up to /spl sim/10 pulses per second (can be increased to 50 pulses per second) and the extracted ion beam current can be up to /spl sim/1 Amp. peak or /spl sim/10 mA time averaged. The ion source extraction voltage was increased to 60 kV corresponding to mean beam energies of up to 150 keV or more because of the ion charge state multiplicity (extraction voltage can be increased to 100 kV if desired). Commisioning of the facility is in progress. Initial emphasis of the R&D programs that will be carried will be in forming tribologically enhanced materials for industrial applications. In this paper we describe the design and operation of the implanter, summarize the preliminary performance parameters that have been obtained, and outline some of the programs we anticipate doing.

Some features of the electrostatic plasma lens as applied to the focusing of moderate-energy, high-current, wide-aperture metal ion beams have been investigated and are described here. Static characteristics within the plasma lens volume have been explored. It is shown that when the potentials applied to the lens electrodes are held constant, the electric field increase with increasing ion beam current is limited by the increase of the potential in the paraxial region of the beam. Some estimates are made of the limiting static electric fields that can be obtained in the plasma lens, based on a quasi-neutral, two-component plasma model with anomalous electron mobility, where it is assumed that the anomalous mobility is caused by the absence of electron correlations when vortex-like structures appear in the hydrodynamically unstable plasma. The results of a theoretical analysis are compared with experimental data. Some results of experiments on the focusing of high-current, large area, heavy metal ion beams are also presented.

Plasma and ion beam methods such as gas and metal ion implantation, plasma immersion ion implantation (PIII), and metal plasma immersion ion implantation and deposition (MePIIID) are introduced as powerful tools to modify the properties of battery electrodes. Three kinds of rechargeable electrochemical cells have been investigated: the lead-acid cell, the nickel alkaline-electrolyte cell, and the lithium cell. It was experimentally shown that (i) metal ion implantation of Ti, V, Cr, Ni, and W into lead and lead-antimony electrodes reduced the corrosion current by more than one order of magnitude, (ii) cobalt ion implantation into nickel electrodes enhanced the interconversion of Ni(OH)2 to NiOOH and the associated cycle life, (iii) nitrogen-PIII resulted in the formation of a nitrided lithium layer on lithium which stabilized the surface against corrosion, (iv) MePIIID with a tungsten plasma reduced the pitting corrosion of aluminum, a current collector for a lithium battery.

We describe the temporal development of the plasma composition of pulsed aluminum plasma streams at various oxygen pressures. The plasma was formed with a vacuum arc plasma source and the time resolved plasma composition was measured with time-of-flight charge-to-mass spectrometry. The temporal development of the plasma composition as well as the Al average ion charge state was found to be a strong function of the oxygen pressure. Oxygen and hydrogen concentrations of up to 0.36 and 0.32, respectively, were found in the first 50 μs of the pulse at oxygen pressures of ⩾5×10−5 Torr. The average charge state of aluminum ions was found to vary from +1.2 to +2.5 depending on the oxygen pressure and the time elapsed after ignition of the arc. These results are of fundamental importance for the understanding of the evolution of the composition (through the plasma composition) and microstructure (through the Al ion flux energy) of alumina thin films produced by pulsed, reactive aluminum plasmas.

Black CuO films are used for improved radiation cooling of, e.g. an r.f. kicker at the Advanced Light Source of Lawrence Berkeley Laboratory. The films are required to be transparent to r.f. fields particularly in the range 1–1.25 GHz, UHV compatible, and very adhesive even after a number of baking cycles. Usual techniques such as wet-chemical coating do not fulfil the requirements for UHV compatibility. A cathodic arc plasma source with a copper cathode was operated in an oxygen atmosphere to form CuO films on the substrate, which was either the anode or was mounted on a substrate holder using a separate anode. The films are single-phase polycrystalline CuO. They are slightly oxygen-rich, adhere very well (pull strength exceeding 85 MPa) and fulfil all UHV requirements. The deposition method is very efficient, and large workpieces up to a surface area of 5000 cm2 have been coated.

Heavy Ion Time-of-Flight Recoil Spectrometry has been used to measure the implant distributions and dose in metal surfaces subject to dual ion implantation. Polished specimens of type 304 stainless steel were simultaneously implanted with both metallic and gaseous species produced from a modified metal vapour vacuum arc ion source (MEVVA). The combination of ions used were Al + O, Cr + O, Zr + O and Ti + N. Results show that the retained doses differ significantly from the expected applied values, and metal-gas implant ratios. In particular, the metal-oxygen systems show an anomalously low retained metal dose.

The ion charge state distribution of vacuum arc plasma depends on its arc operating ("burning") voltage. Increase of the arc operating voltage leads to dissipation of more energy in the collisional cathode-spot plasma and as a result the average ion charge state increases. One way of increasing the arc voltage is to superimpose current spikes on the arc current. The influence of single, double, and multiple current spikes on the charge state distribution has been investigated for various cathode materials.

Microstructure modification of amorphous carbon films containing about 30 at.% hydrogen (a-CHx) and nonhydrogenated amorphous carbon (a-C) films was accomplished with a vacuum arc metal plasma implanter and a cathodic arc plasma system, respectively. The films were implanted with Si, Ti, Hf, W, and Al of ion doses approximately equal to 1 and 3 × 1016 ions/cm2 and mean ion kinetic energies in the range of 3–70 keV, depending on the implantation method. Simulation results demonstrated a profound effect of the size of implant species, ion dose, mean ion kinetic energy, and implantation processes on the implant spatial distributions. Statistical roughness results showed a negligible effect of ion implantation on the film surface topography. Elastic recoil spectroscopy revealed a decrease in the hydrogen content of the a-CHx films due to the ion bombardment. A monotonic decrease in the Raman scattering intensities and a downward shift of the carbon peak position occurred with increasing ion dose for both types of films and implantation techniques. Nanoindentation experiments demonstrated an effect of ion implantation on the apparent film hardness, depending on the flux and kinetic energy of implanted species. Changes in the hardness characteristics of the implanted films are interpreted in terms of the chemical reactivity of implant elements and microstructure modifications caused by irradiation damage, dehydrogenation, and higher contents of tetrahedral (s p3) carbon hybridization due to carbide bond formation.

We describe some experimental investigations of the focusing properties of an electrostatic plasma lens based on the use of permanent magnets instead of conventional current-driven coils. These investigations were performed at the IP NASU (Kiev) and at the LBNL (Berkeley) using moderate energy, high current, broad, heavy ion beams. Computer simulation of physical processes involved for typical experimental conditions was also carried out.

The present paper deals with peculiarities of vacuum arc ion sources employed to generate beams of gas and metal ions with the controllable ratio of ions of each type in a beam. The design and parameters of the sources are presented. The mass- charge state of ion beams is studied, and the dependence of the gas ion fraction in a beam on the length of a discharge gap is analyzed. Also presented in the paper is a new version of the design of the TITAN source and its parameters.

We describe a simple and inexpensive diagnostic for rapid measurement and display of the radial profile of the ion beam generated by an experimental ion source. The technique may be useful for other kinds of beams also.

The stabilization of a hot‐electron plasma in a simple mirror geometry is investigated. Controlled quantities of neutral gas generate a cold plasma through hot‐electron ionization. Increasing stability is found with increasing gas pressure. The pressure required for stabilization is found to be inversely proportional to the ionization cross section of the type of neutral gas, indicating that the number of cold electrons is the key stabilizing quantity. The stabilization requires the cold electron density to be at least the same order of magnitude as the hot electron density. Line tying to external surfaces does not play a role in the stabilization. A theory in which the electrons, but not the ions, can be treated in the drift approximation is most closely applicable to the experiment. Reasonable agreement between theory and experiment has been obtained.

Tormac (Toroidal Magnetic Cusp) is a plasma confinement concept combining the favorable MHD stability properties of a cusp geometry with the good particle confinement inherent to closed field geometry, A Tormac plasma has two regions: an interior region in which a toroidal bias or studding field is embedded, and an exterior or surface region confined by mirror trapping along open field lines. The combination of these two regions is expected to lead to a configuration having confinement substantially superior to that of a mirror. and to allow the plasma to be stable at high {beta}. The Tormac V experiment is an attempt to establish such a configuration and to investigate characteristic behavior of the Tormac plasma. In this paper we describe the Tormac concept. the Tormac V experimental set-up. and the results obtained.

The perpendicular ion temperature of a barium plasma contained in a double‐ended Q machine has been measured by a spectroscopic technique. When the plasma is “ion‐rich”, good agreement is found between the measured ion temperature and the hot‐plate temperature, while in the “electron‐rich” regime, the ion temperature is elevated above the hot‐plate temperature. The increased ion temperature can be well accounted for by the energy input through the acceleration of ions through the electron sheath and their consequent thermalization.