Wavelet Methods for Studying the Onset of Strong Plasma Turbulence

Our New Paper Has Been Released! 

Please also enjoy some short movies that help support points throughout the paper.

Recent simulations have demonstrated that coherent current sheets dominate the kinetic-scale energy dissipation in strong turbulence of magnetized plasma. Wavelet basis functions are a natural tool for analyzing turbulent flows containing localized coherent structures of different spatial scales. Here, wavelets are used to study the onset and subsequent transition to fully developed turbulence from a laminar state. Originally applied to neutral fluid turbulence, an iterative wavelet technique decomposes the field into coherent and incoherent contributions. In contrast to Fourier power spectra, finite time Lyapunov exponents (FTLE), and simple measures of intermittency such as non-Gaussian statistics of field increments, the wavelet technique is found to provide a quantitative measure for the onset of turbulence and to track the transition to fully developed turbulence. T…

ICMMES Presentation On: Rise of Intelligent Algorithms in Science and Engineering

Last month I gave a talk at ICMMES on The Rise of Intelligent Algorithms in Science and Engineering, check it out here:Talk at ICMMES

Presentation: Petascale Space Weather Simulations That Reveal 3D Structure of Earth's Ion Foreschock


Intelligent End-to-End Petascale Framework

I have always felt a strong bond with the sea, and that shaped my approach to science and business, enabling me to work on a rich variety of topics and domains.

Surprisingly, there exists a close analogy between surfing and paradigm-shifting events in science and business. The following figure from (How to Find & Catch Unbroken Waves)is useful in making this connection.

To surf a wave, you need the right conditions in the ocean to create surfable waves. And then you need to possess an instinct about which wave to catch, and when to catch it. It can mean the difference between being at the bleeding edge, where the technology is at high risk of being unreliable and has not gained traction, or the cutting edge, where the technology is past the proof point and gaining traction.

If you catch a wave too early when it is only a bump, then you will not be able to ride it. If you catch a wave too late when it is breaking or has already broken, then not only will you not…

Computer Simulations and Space Weather

In the 1990s, the use of computer simulations as a virtual environment to model complex physical systems was gaining momentum, driven to a large extent by increase in computational power.A common simulation technique consists of dividing the simulation domain into a computational grid, initializing the system and then updating the state of the system over time.
At the time, I was looking into computer simulation techniques with an eye towards applications in plasma physics, such as fusion, space physics such as space weather, among others. A common characteristic among these applications is that different parts of the system evolve at different rates in time. An ideal algorithm would intelligently adapt the time step at each computational grid based on local conditions to achieve a desired accuracy. As it turns out, this is a very challenging task for the algorithms.The standard techniques, generally called time-stepped based, faithfully update the system at equal time steps, leading…