![]() Inside glass, however, the light travels more slowly than in vacuum so some of these electrons are indeed faster-than-light. These electrons rush through the glass target behind. ![]() (b) the time trace for the Cherenkov emission measured in the experiment. Cherenkov emission in the form of cones is emitted by these electrons travelling faster than light in glass. (a) A high power laser pulse creates mega-ampere electron current pulses. Figure 2: The table-top laser experiment at the Tata Institute of Fundamental Research, Mumbai. #LASER PULSE FASTER THAN LIGHT FREE#The electron pulses in question were produced by a high power laser in TIFR (100 terawatt Titianium: Sapphire laser to be precise) irradiating a glass target which was hosted in a vacuum chamber on a table top (see figure 1 below). By focusing the laser beam to a micrometre spot, the team were able to create such a high intensity that electrons in the glass were instantly propelled from their positions and catapulted to speeds so fast that they approached the speed that light itself would travel in free space. So really handy then - but how do you generate these electron pulses in the first place? ![]() We're talking mimicking conditions found in stars and the cores of planets, in a laboratory at RAL! Not only that but these incredible electrons are slap-bang in the centre of core technologies used to produce advanced X-ray, electron and ion sources for industrial and medical applications. This research is therefore incredibly valuable for improving our understanding of the transport of energetic electrons through matter.įigure 1: Ilustration by Helen Towrie, CLFīut why is this question so important? Well, things start to get really interesting when you consider that these electrons can drive giant current pulses (on the millions of ampere scale!) that are capable of generating some of the most exotic states of matter to ever be produced by man. Despite previous studies into hot-electron transport through solids, very little was previously known about the actual time that electrons spend inside a solid while dissipating their energy. Mainly, because understanding the transport of these electrons in the target involves a lot of complex physics. When completing their research, an international team of scientists from the Tata Institute of Fundamental Research (TIFR) in India, STFC's Central Laser Facility and Celia in France, had one question in mind 'when fast electrons transit a solid, do they pass straight through the medium or do they stay within the material for a while instead?' Now, laser technology has provided answers.īy focusing a high power laser pulse on the surface of a glass target, the team were able to produce electrons that travelled at near-light speeds. You get answers - and some really fast electrons all of which has been chronicled in a recent paper, published in Physical Review Letters. ![]()
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