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Click on the images below to play Quicktime videos. You may need the Quicktime plugin. |
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The currents of Alfven waves with several "m" numbers rendered as snakes. |
| This image appears in an article accepted for publication in the IEEE Transactions on Plasma Science, Special Issue: Images in Plasma Science, 2005, authors: Gekelman and Vincena | |
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The interaction of two shear Alfven waves. The current parallel to the background magnetic field (the long direction in the movie) is carried by the electrons--red streamlines are parallel and blue are anti-parallel. The current closes in the perpendicular direction via the ion-polarization current which are here visualized using the central plane of vectors. |
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Measurements of the magnetic field (vectors) and corresponding parallel currents produced in the aftermath of the explosion of dense, laser-produced plasma into a lower-density background plasma. The fields and currents are part of an Alfven wave.
Note: This movie is 17 MB. |
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Streamlines of current from an azimuthally symmetric Alfvén wave, launched by modulating a current filament with transverse size on the order of the electron collisionless skin depth (and the ion-sound gyroradius: cs/wci). This wave is at a frequency close to the ion-cyclotron frequency, so that the ExB drifts of the ions and electrons no longer cancel exactly and the wave develops both an oscillating azimuthal electric field and axial magnetic field. The "organic" current of a shear Alfven wave. The scale is 2 meters from top to bottom and 40 cm across. What is shown is 1/2 wavelength. |
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high-quality, still image of the same data will appear in an article
accepted for publication in the IEEE Transactions on Plasma Science,
Special Issue: Images in Plasma Science, 2005, authors: Vincena and
Gekelman. See also, http://plasma.physics.ucla.edu/bapsf/papers/beach_pop.pdf for in-depth information on the experiment which produced the data for this movie. Contact: vincena@physics.ucla.edu for more information. |
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We created a four-minute video to explain some of the visualization techniques we employ. We are posting two versions of this movie. The smaller version is 8 MB; the larger version is 18 MB. The larger video is better quality. The original movie is full screen NTSC (640X480) and takes up more than 250 MB. Obviously both the posted versions sacrifice size and quality to achieve a (barely) reasonable size. |
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A comparison between theory and experiment of the time-varying magnetic field vectors of two closely spaced Alfven wave parallel current channels. |
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In this case, kHz-frequency Alfven waves can be produced by a burst of hot electrons created using a pulsed microwave source operating at several GHz. |
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The technique of laser-induced fluorescence (LIF) has been used for the first time to measure the vector cross-field flow of ions in the presence of Alfven waves. Here, the 3x3 grid of pink arrows are the LIF measurements within the larger cross-field plane of wave magnetic field measurements. The ion motion is due to both the polarization and E-cross-B drifts. |
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Another example of two interacting Alfven waves. The wave magnetic field vectors are largest between the two current filaments which are driven out of phase at a frequency below the ion-cyclotron frequency. |
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Simulation of expulsion of magnetic field in a laser plasma interaction. |
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A galaxy is texture mapped on an Alfven wave measured at 2000 locations on a plane. It is a backwards wave. Check out the motion of the ripples. |
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A computer-generated QuickTime simulation of flying through a model city at helicopter speeds and then flying through the same city at .99 times the speed of light. |
