Generation of multiple bipolar voltage pulses for a phase rotation LIA
In the year 2000, a design concept of a Neutrino Factory based on Muon Storage Ring was studied at FNAL. To treat high energy spread of muons that come out of a target and decay channel and are to be accelerated before they go into the storage ring, a phase rotating scheme using a long-pulse accelerating system has been proposed. In this system the accelerating voltage is to be shaped to correct the energy spread. To implement this approach, the pulse power system has been suggested that allows forming a bipolar accelerating voltage pulse with the predefined shape. This report addresses some issues of the pulse shape optimization and describes main features of the accelerating system comprising an accelerating structure similar to that of a linear induction accelerator (LIA) and a pulser that drives it.
Applications of amorphous magnetic materials at very‐high magnetization rates (invited)
Amorphous ferromagnetic alloys are finding increased application in high‐energy pulse‐power systems and in high‐frequency switched‐mode power supplies. The peak powers in these applications differ by several orders of magnitude as do the core sizes; however, these applications do share similar very‐high magnetization rates often measured in teslas per microsecond. In this paper the important characteristics of amorphous magnetic materials used at high magnetization rates are reviewed. Domain models for very‐high magnetization rates are discussed. The effects on magnetic losses of differing voltage waveform excitations are calculated for applications which require nonconstant rates of dB/dt. Finally, several applications utilizing magnetic amorphous alloys at high magnetization rates, in both research devices and potential commercial applications, are described. Pulse‐power devices based on amorphous alloy cores have already reached multiterawatt peak output power levels with pulses shorter than 100 ns. Petawatt peak‐power devices are on the drawing boards.Amorphous ferromagnetic alloys are finding increased application in high‐energy pulse‐power systems and in high‐frequency switched‐mode power supplies. The peak powers in these applications differ by several orders of magnitude as do the core sizes; however, these applications do share similar very‐high magnetization rates often measured in teslas per microsecond. In this paper the important characteristics of amorphous magnetic materials used at high magnetization rates are reviewed. Domain models for very‐high magnetization rates are discussed. The effects on magnetic losses of differing voltage waveform excitations are calculated for applications which require nonconstant rates of dB/dt. Finally, several applications utilizing magnetic amorphous alloys at high magnetization rates, in both research devices and potential commercial applications, are described. Pulse‐power devices based on amorphous alloy cores have already reached multiterawatt peak output power levels with pulses shorter than 100 ns. Pe...
Persistence and Change in Minkowski Spacetime
There are famously two main metaphysics of persistence, namely three and four-dimensionalism. Both yield a particular solution to the so called puzzle of change. I argue that typical three-dimensionalist solutions to the puzzle face insurmountable difficulties even in the simplest relativistic setting, that of Minkowski spacetime