Although wild waves have never been the subject of direct research by Prof. Falkovitz from the Department of Physics of Complex Systems at the Weizmann Institute of Science, most of his scientific work was devoted to the study of the chaotic flow known as turbulent flow, which also characterizes the flow in the ocean
One summer day more than twenty years ago, they were wading Prof. Gregory Falkowitz and his five-year-old son in shallow, calm ocean waters at a beach near Los Angeles, when suddenly they were swept away by a three-meter-high wave that came as if from nowhere. The two did get out unscathed, but Prof. Flakovitz, not surprisingly, was shocked - perhaps, among other things, because Hegel took his eyeglasses with him and he needed them to drive back to the hotel. Either way, he was fascinated by the experience: the face-to-face meeting with what is known as a "wild wave" or "crazy wave", reminded him how shrouded in mystery the origins of this rare phenomenon are.
Although wild waves were never the subject of direct research by Prof. Flakovitz from the Department of Physics of Complex Systems at the Weizmann Institute of Science, most of his scientific work was devoted to the study of the chaotic flow known as turbulent flow, which also characterizes the flow in the ocean. In a new study with research student Michal Shavit, The scientists developed a new way to find a certain degree of order in these chaotic systems. Using mathematical tools taken from information theory, the two showed that even given a weak eddy flow - for example, when the wind raises ripples on the surface of the water - they may have a very close relationship with each other, when one holds significant information about the other. Therefore, over time, it is possible to measure waves of a certain wavelength and derive from this information also about waves that were not measured - in a range of other wavelengths.
"Information theory helped us make progress in understanding turbulence," declares Prof. Falkowitz. "The research carries good news when it comes to the possibility of building turbulent flow models, since the findings mean that the existing information can be used to fill in the missing pieces of the puzzle," adds Shavit. The good news is not only relevant to flow research, but also to many other diverse fields, from civil engineering to experimental physics. For example, when building a port or pier, one must know as much as possible about the strength of the waves in the area, including the probability that particularly strong waves will be created as a result of interactions between weaker waves. The new research may also be relevant to the development of advanced communication in optical fibers that simultaneously transmit many waves of information, since with the increase in the density of information, it will be essential to know how these waves may interfere with each other. Another field of application is plasma research - to understand how the ionized gas and the electromagnetic waves needed to create the plasma affect each other.
The use of information theory in the study of turbulent flow constitutes a change from the way this topic has been studied so far. "Throughout the twentieth century, the study of turbulence was focused exclusively on energy - wind energy or energy of currents or other physical variables. We, on the other hand, focused on information - how much can be learned about certain waves from observing other waves," says Prof. Falkovitz. To this end, the scientists used some of the concepts developed in 1922 by the Hungarian physicist Leo Szilard, then 24 years old. Szilard, who in his doctoral thesis laid the foundations for information theory, coined, among other things, the concept of a "bit" - a unit of information that can be transferred from place to place .
Prof. Flakovitz and Shavit developed formulas that use this concept to determine how many bits of information about a third wave can be obtained from the interrelationship between two waves that have concrete information about them. This is the simplest case of prediction within a turbulent system. To predict occurrences in reality where there are interactions between tens if not hundreds of waves - it is necessary to continue to research, but the initial formulas already form the basis for a new approach to turbulence.
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