It has been recognized both by NASA (2018 Strategic Plan) and the National Academy of Sciences (2019 Search for Life report) that the future of space exploration will require challenging missions to nearby planets and moons. Such missions will involve high-speed aircraft atmospheric entries, which become increasingly technical in thick atmospheres, such as the atmospheres of gas giants, due to the resulting extreme heating of the spacecraft. This motivates the desire to develop and test the next generation of heat shields that can protect spacecrafts during such ambitious entries. To address this problem of high significance to the U.S. goals in space exploration, we collaborate with Dr. Dmitri Orlov and Dr. Igor Bykov from University of California San Diego in a project where we study what happens to aircraft heat shield materials when exposed to extreme conditions....

Fig. 1. a) Non-interacting particles move randomly (normal diffusion.) b) Correlated particles can make huge jumps in space (anomalous diffusion.) In a famous 1972 publication, Philip Anderson argued that the behavior of complex systems cannot be reduced to the interactions of elementary entities. Instead, at each level of complexity entirely new properties emerge due to the many-body correlations involved. Simply put, more is different. While non-interacting particles move in a random fashion, called normal diffusion, correlated particles move in a less random way, called anomalous diffusion. Anomalous diffusion is so common in the natural world that scientists often conclude: anomalous is normal. The marriage between increasing complexity and anomalous transport often results in turbulent dynamics of the many-body system. Dusty plasmas are ideal media for the investigation of these phenomena. In this project we study turbulence in a dusty plasma by computing the spectrum of energies available to the dust particles as a function of random disorder and properties of nonlocal interactions mediated by the plasma. We argue that at critical scales within the system, anomalous dust diffusion, guided by nonlocal interactions, leads to enhancement of energy transport and increased probability for turbulent dynamics. These theoretical predictions are compared against results from many-body simulations and dusty plasma experiments conducted on board the International Space Station....

It is often pointed out that plasma is the most abundant form of visible matter throughout the universe, which makes it not surprising that a large class of plasma-related phenomena have practical applications in various fields of science and industry. However, the vast majority of plasma research studies are hardly thorough without understanding how plasma interacts with other forms of matter. From the investigation of star and planet formation to the cutting-edge research in fusion technology, materials science, and low temperature plasma physics, scientists cannot ignore the presence of small solid or liquid particles (also called dust) existing within plasmas. Most environments containing plasma are also likely to contain dust due to both plasma-surface interactions and dust particle chemical growth. The physics of these dusty plasmas has naturally evolved as a cross-disciplinary research field encompassing a wide range of topics relevant to both fundamental science and technological development (Fig. 1)...

A common issue in the study of laboratory plasma is the perturbative nature of electric probes, such as the Langmuir probe, commonly used to obtain the discharge characteristics. Dusty plasma systems offer an alternative approach, where the dynamical processes within the plasma can be studied by optically tracking the motion of individual dust grains suspended in the discharge. Due to their mesoscopic size, the dust particles are less perturbative than a typical probe and more sensitive to changes in the plasma environment. Therefore, dusty plasmas provide a powerful diagnostics tool for the investigation of various phenomena, including plasma-material interactions, electric field mapping, plasma sheath characteristics, etc. The goal of this research project is to develop a set of dust diagnostics techniques, which will be employed in the characterization of new discharge devices, such as CASPER Cell 3 shown below....

This is a series of research projects that aims to incorporate newly-developed mathematical techniques in the study of exotic transport phenomena in physical systems characterized by disorder, non-local interactions, and correlated effects. Specifically, we focus on the application of spectral theory and fractional calculus to important phenomena, such as turbulence, streaming instability, and conductivity in low-dimensional materials. Our work is a generalization of the famous theory of Anderson localization introduced in 1958 by Philip Anderson, for which he received the Nobel Prize in Physics in 1977. While the original question addressed by Anderson was focused on localization due to disorder, our work aims to identify the physical systems where delocalization can exist, despite the presence of disorder. Anderson ended his Nobel Prize speech with a reference from Lewis Carroll, emphasizing how complex, yet fascinating a simple transport question can be....

The self-organization and stability of macroscopic astronomical objects, such as stars and galaxies throughout the universe, is dominated by the force of gravity. In contrast, when the structures are microscopic, such as systems of atomic and subatomic particles, the same processes are guided by nuclear forces and quantum effects. As one follows the growth of an astronomical body from the subatomic level up, a natural question emerges: What fundamental mechanisms dictate self-organization and stability in the transitional (mesoscopic) range, where the spatial scale is neither small nor large? A few decades ago, the international complex plasma community recognized that the fundamental questions of  mesoscopic physics can be explored using a series of dusty plasma experiments in space. Currently, the most effective way of achieving microgravity conditions is to perform these experiments on board the International Space Station (ISS). In February 2001, the dusty plasma experiment PKE Nefedov became the first natural science experiment installed on board the ISS. Since then, dusty plasma research on the ISS has revealed that the mesoscopic structures can exhibit a variety of condensed and soft matter phenomena including, crystallization and melting, wave instabilities and mode coupling, formation of vortices and self-excited turbulences, and electrorheology. The current dusty plasma lab installed on the ISS, Plasma Kristall-4 (PK-4) , is the first project of this kind with direct involvement of US research groups, one of which is the CASPER group....