32998739
High-current heavy ion beams in the electrostatic plasma lens
We describe applications of the electrostatic plasma lens for manipulating and focusing moderate-energy, high-current, broad, heavy ion beams. Use of a plasma lens in this way has been successfully demonstrated in a series of experiments carried out collaboratively between the Institute of Physics, National Academy of Sciences, Kiev, Ukraine, and the Lawrence Berkeley National Laboratory, Berkeley, CA, in recent years. Here, we briefly review the plasma lens fundamentals, peculiarities of focusing heavy ion beams, and summarize some recent developments (experiments, computer simulations, theory). We show that there is a very narrow range of low magnetic field for which the optical properties of the lens improve markedly. This opens up some attractive possibilities for the development of a new-generation compact lens based on permanent magnets. Preliminary experimental results obtained at Kiev and Berkeley on the operation of a permanent magnet plasma lens for manipulating wide aperture high-current heavy ion beams are presented and summarized.
101301970
High current ion source
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.
58933464
Surface modification of nickel battery electrodes by cobalt plasma immersion ion implantation and deposition
Abstract Nickel hydroxide is the electrochemically active material in the positive electrode of several important rechargeable alkalineelectrolyte batteries. It is believed that the Ni 2+ in nickel hydroxide is converted to Ni 3+ in nickel oxy-hydroxide as the electrode is electrochemically oxidized during the battery charging process, and the reverse reaction (electrochemical reduction) occurs during the battery discharge. However, the details of this process are not completely understood. Because these electrochemical reactions involve surface charge-transfer processes, it is anticipated that the modification of the electrode surface may result in an improved battery performance. We used broad-beam metal ion implantation and the new technique of metal plasma immersion ion implantation and deposition (MePIIID) to add cobalt and other species to the nickel electrode surface. The principle of the latter technique is explained in detail. It has been demonstrated that implanted and deposited cobalt ions (acting as electronic dopants) balance the huge difference in the conductivities of nickel hydroxide and nickel oxy-hydroxide. This beneficial effect promotes a more complete interconversion between the nickel hydroxide and the nickel oxy-hydroxide and leads to a higher capacity and efficiency of the nickel hydroxide electrode in the batteries applications.
121242075
High current metal ion beam transport in the UNILAC injector at GSI
Abstract 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.
119595199
Transport and acceleration of high current uranium ion beams
Abstract 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.
120372071
A NEW METHOD FOR ION CHARGE STATE ANALYSIS
We present results showing charge‐state separation of an ion beam in a purely cylindrical geometry, using the azimuthal magnetic field of a straight conductor. This geometry, which we refer to as a current coaxial lens, has advantages for the analysis of intense ion beams where it is important to minimize space‐charge blowup of the beam due to loss of space‐charge neutralization.
118519718
Gauges and cosmological backreaction
We present a formalism for spatial averaging in cosmology applicable to general spacetimes and coordinates, and allowing the easy incorporation of a wide variety of matter sources. We apply this formalism to a Friedmann-Lemaȋtre-Robertson-Walker universe perturbed to second-order and present the corrections to the background in an unfixed gauge. We then present the corrections that arise in uniform curvature and conformal Newtonian gauges.
15014169
Multi-wavelength INTEGRAL network (MINE) observations of the microquasar GRS 1915+105
We present the international collaboration MINE (Multi-lambda Integral NEtwork) aimed at conducting multi-wavelength observations of X-ray binaries and microquasars simultaneously with the INTEGRAL gamma-ray satellite. We will focus on the 2003 March-April campaign of observations of the peculiar microquasar GRS 1915+105 gathering radio, IR and X-ray data. The source was observed 3 times in the plateau state, before and after a major radio and X-ray flare. It showed strong steady optically thick radio emission corresponding to powerful compact jets resolved in the radio images, bright near-infrared emission, a strong QPO at 2.5 Hz in the X-rays and a power law dominated spectrum without cutoff in the 3-300 keV range. We compare the different observations, their multi-wavelength light curves, including JEM-X, ISGRI and SPI, and the parameters deduced from fitting the spectra obtained with these instruments on board INTEGRAL.
119438526
Microquasar Observations with MERLIN
A series of observations of microquasar GRS1915+105 were made by the MERLIN telescope array in the spring of 2003 at 18 cm. The images show polarization in the jet components, with two epochs displaying Faraday rotation of about 2500 rad/m2. This effect is a demonstration of the similarities between microquasars and extragalactic jets.
116966118
Concerning the statistics of cosmic magnetism
Magnetic fields appear to be a generic feature of the early universe and are a natural source of secondary CMB non-Gaussianity. In recent years the statistical nature of the stresses of a primordial magnetic field has been well studied. In this paper we confirm and extend these studies at one- and two-point level, and present analytical results for a wide range of power-law spectra. We also consider two non-power law cases of interest: a blue spectrum with an extended damping tail on small scales, which could be generated by the non-linear mixing of density and vorticity; and a red spectrum with a damping tail on large scales. We then briefly consider the CMB impacts that result from such fields. While this paper focuses on the one- and two-point moments, the techniques we employ are designed to ease the analysis of the full bispectra induced by primordial magnetic fields.
53709253
Non-Gaussianity from cosmic magnetic fields
Magnetic fields in the early Universe could have played an important role in sourcing cosmological perturbations. While not the dominant source, even a small contribution might be traceable through its intrinsic non-Gaussianity. Here we calculate analytically the one-, two-, and three-point statistics of the magnetic stress energy resulting from tangled Gaussian fields, and confirm these with numerical realizations of the fields. We find significant non-Gaussianity, and importantly predict higher order moments that will appear between the scalar, vector, and tensor parts of the stress energy (e.g., scalar-tensor-tensor moments). Such higher order cross correlations are a generic feature of nonlinear theories and could prove to be an important probe of the early Universe.