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Full-Text Articles in Physics
Testing The Well-Posedness Of Characteristic Evolution Of Scalar Waves, Maria Babiuc-Hamilton, Heinz Otto Kreiss, Jeffrey Winicour
Testing The Well-Posedness Of Characteristic Evolution Of Scalar Waves, Maria Babiuc-Hamilton, Heinz Otto Kreiss, Jeffrey Winicour
Maria C. Babiuc-Hamilton
Recent results have revealed a critical way in which lower order terms affect the well-posedness of the characteristic initial value problem for the scalar wave equation. The proper choice of such terms can make the Cauchy problem for scalar waves well posed even on a background spacetime with closed lightlike curves. These results provide new guidance for developing stable characteristic evolution algorithms. In this regard, we present here the finite difference version of these recent results and implement them in a stable evolution code. We describe test results which validate the code and exhibit some of the interesting features due …
Binary Black Hole Waveform Extraction At Null Infinity, Maria Babiuc-Hamilton, Jeffrey Winicour, Yosef Zlochower
Binary Black Hole Waveform Extraction At Null Infinity, Maria Babiuc-Hamilton, Jeffrey Winicour, Yosef Zlochower
Maria Babiuc-Hamilton
In this paper, we present a work in progress toward an efficient and economical computational module which interfaces between Cauchy and characteristic evolution codes. Our goal is to provide a standardized waveform extraction tool for the numerical relativity community which will allow CCE to be readily applied to a generic Cauchy code. The tool provides a means of unambiguous comparison between the waveforms generated by evolution codes based upon different formulations of the Einstein equations and different numerical approximation.
Gravitational Wave Extraction Based On Cauchy–Characteristic Extraction And Characteristic Evolution, Maria Babiuc-Hamilton, Yosef Zlochower, Béla Szilágyi, Ian Hawke
Gravitational Wave Extraction Based On Cauchy–Characteristic Extraction And Characteristic Evolution, Maria Babiuc-Hamilton, Yosef Zlochower, Béla Szilágyi, Ian Hawke
Maria Babiuc-Hamilton
We implement a code to find the gravitational news at future null infinity by using data from a Cauchy code as boundary data for a characteristic code. This technique of Cauchy–characteristic extraction (CCE) allows for the unambiguous extraction of gravitational waves from numerical simulations. We first test the technique on non-radiative spacetimes: Minkowski spacetime, perturbations of Minkowski spacetime and static black hole spacetimes in various gauges. We show the convergence and limitations of the algorithm and illustrate its success in cases where other wave extraction methods fail. We further apply our techniques to a standard radiative test case for wave …
Testing Numerical Evolution With The Shifted Gauge Wave, Maria Babiuc-Hamilton, Jeffrey Winicour, B´Ela Szilágyi
Testing Numerical Evolution With The Shifted Gauge Wave, Maria Babiuc-Hamilton, Jeffrey Winicour, B´Ela Szilágyi
Maria Babiuc-Hamilton
Computational methods are essential to provide waveforms from coalescing black holes, which are expected to produce strong signals for the gravitational wave observatories being developed. Although partial simulations of the coalescence have been reported, scientifically useful waveforms have so far not been delivered. The goal of the AppleswithApples (AwA) Alliance is to design, coordinate and document standardized code tests for comparing numerical relativity codes. The first round of AwA tests has now been completed and the results are being analyzed. These initial tests are based upon the periodic boundary conditions designed to isolate performance of the main evolution code. Here …