Jean-Luc's Movies

Jean-Luc Movie: /NCSA1999/BrillWaves/BW4_128_0.04/PsiAlpha

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Subcritical Brill Wave at amplitude A=4, similiar visualization setup as in Psi4Alpha, but now also including the Re{Y0} component of the gravitational field. Y0 can be interpreted as the ingoing component of a gravitational field in an asymptotically Schwarzschild spacetime.

Re{Y0} is rendered as bluegreen volumetric clouds. High intensity values are indicated by yellow colors, medium values by green colors, low values by blue. Only values larger than zero are shown.

Initially, Re{Y0} and Re{Y4} are identical, so they occupy the same space with same intensity and the result of the red (Y4) and blue (Y0) volumetric clouds is a violet cloud. But immediatly after starting the evolution, the violet cloud seperates into a red cloud (Y4) running outwards, and a blue-green cloud (Y0) running inwards. Again, the lapse function is shown below.

When the green Y0-pulse has reached the origin (aorund T ~ 5), it can't collapse further, but bounces back, which is visible as a red Y4 pulse, originating at the center of the Brill Wave. In the Psi4Alpha animation sequence, this pulse appears to come `out of nothing', but when displaying Y0, too, one actually sees that the large pulse of gravitational energy, which is carrying most of the entire space time's energy, is the `bounced' initially infalling gravitational energy.

Around T~12 one may recognice a blue Y0 coming inwards from the bounding box. This is an computational artefact, some virtual reflection of the outgoing Y4 pulse. Such artefacts will go away when using higher grid resolutions, better boundary conditions, and so on, but it at least shows the usefulness to display Y0 as an indicator for the ingoing gravitational field (independent of the physical validity).

Simulation code: Miguel Alcubierre , Gabrielle Allen , Bernd Bruegmann , Gerd Lanfermann , Lars Nerger , Ed Seidel , Ryoji Takahashi, Tom Goodale, Daniel Holz, Steve Brandt, Paul Walker, Thomas Radke (AEI)
John Shalf (NCSA)
Toni Arbona, Joan Masso and Carles Bona (University of the Balearic Islands)
Wai-Mo Suen , Malcolm Tobias (WashU)
( AEI , WashU )

Mpeg Movie: PsiAlpha.mpg
( Mpeg -