Predicting the relativistic periastron advance of a binary without curving spacetime

Relativistic Newtonian Dynamics, the simple model used previously for predicting accurately the anomalous precession of Mercury, is now applied to predict the periastron advance of a binary. The classical treatment of a binary as a two-body problem is modified to account for the influence of the gravitational potential on spacetime. Without curving spacetime, the model predicts the identical equation for the relativistic periastron advance as the post-Newtonian approximation of general relativity formalism thereby providing further substantiation of this model.Comment: 6 pages, 2 figure

Pulsed Power Forming

R&D and application work in the sphere of Pulsed Power Forming (PPF) is well known and has been documented since the 1960's, along with its advantages. Pulsed Power Forming applications, which have been developed at Pulsar Ltd over the last decade, are described in this paper. Special equipment and tools for forming have been designed, developed, and manufactured, utilising pulsed magnetic fields. Theoretical and experimental research has been carried out to determine the magnetic field distribution in certain types of solenoids for diameters up to 600 mm. The software for mechanical pressure simulation and calculation has been carried out. Research and application of forming by electrical discharge into liquid medium have been carried out with higher deformation than it has been attained by the classic processes. Flat forming, cutting, and/or perforating of very thin materials (with thicknesses in the range of 0,1 up to 0,3 mm), such as aluminium, steel, stainless steel, nickel alloys, etc., have been made by applying high magnetic field with elastic medium. In addition, forming and cutting of a steel tube with ~100 mm OD and a wall thickness up to 3 mm have been executed using direct high pulse magnetic field action. Aluminium tubes with OD ~100 mm and a wall thickness less than 0,5 mm have also been similarly processed

Magnetic Pulse Acceleration

The present work is dedicated to describing works in the spheres of simulation, calculation, and experimental results of acceleration by pulsed electromagnetic forces where strain rates of 10,000 - 50,000 s^(-1) are common. The goal is to design a multidisciplinary model that will overcome the shortcomings of normal simulation methods that solve the EM field and then apply the solution in a mechanical analysis. Improved numeric models for virtual simulation of magnetic pulse processes are detailed, along with the pulse-power equipment and a special measurement system developed to verify these models and to determine material property data. These measure both radial velocity and axial speed (collision-point progression) for tube forming and / or welding processes, while logging the pulse current and magnetic field. The results show good a correlation between test and multiphysics model and provide valuable new insights, as well as an extraction of critical parameters by way of a comparison between calculated and measured data for materials such as aluminum alloys, copper, and steel

Exchange coupled perpendicular media

The potential of exchange spring bilayers and graded media is reviewed. An analytical model for the optimization of graded media gives an optimal value of the magnetic polarization of Js = 0.8 T. The optimum design allows for thermally stable grains with grain diameters in the order of 3.3 nm, which supports ultra high density up to 5 to 10 Tbit per inch2. The switching field distribution is significantly reduced in bilayer media and graded media compared to single phase media. For the graded media the switching field distribution is reduced by about a factor of two. For bilayer media the minimum switching field distribution is obtained for soft layer anisotropies about one fifth of the hard layer anisotropy. The influence of precessional switching on the reversal time and the reversal field is investigated in detail for magnetic bilayers. Exchange spring bilayers can be reversed with field pulses of 20 ps.Comment: submitted to JMMM, 'Current Perspectives; Perpendicular recording

A Statistical Analysis of the SOT-Hinode Observations of Solar Spicules and their Wave-like Behavior

We consider a first important parameter of spicules as observed above the solar visible limb: their apparent diameter as a function of the height above the limb which determines their aspect ratio and leads to the discussion of their magnetic origin using the flux tube approximation. We found that indeed spicules show a whole range of diameters, including unresolved "interacting spicules" (I-S), depending of the definition chosen to characterize this ubiquitous dynamical phenomenon occurring into a low coronal surrounding. 1-D Fourier amplitude spectra (AS) made at different heights above the limb are shown for the first time. A definite signature in the 0.18 to 0.25 Mm range exists, corresponding to the occurrence of the newly discovered type II spicules and, even more impressively, large Fourier amplitudes are observed in the 0.3 to the 1.2 Mm range of diameters and spacing, in rough agreement with what historical works were reporting. Additionally, some statistically significant behavior, based on AS computed for different heights above the limb, is discussed. "Time slice or x-t diagrams" revealing the dynamical behavior of spicules are also analyzed. They show that most of spicules have multiple structures (similarly to the doublet spicules) and they show impressive transverse periodic fluctuations which were interpreted as upward kink or Alfven waves. Evidence of the helical motion in spicules is now well evidenced, the typical periods of the apparent oscillation being around 120 sec. A fine analysis of the time-slice diagram as a function of the effective heights shows an interesting new feature near the 2 Mm height. We speculate on the interpretation of this feature as being a result of the dynamical specificities of the spicule helical motion as seen in these unprecedented high resolution HCaII line emission time series.Comment: 21 pages, 8 figurs, 1 tabl