Dusty plasmas are ubiquitous throughout the universe, spanning laboratory and industrial plasmas, fusion devices, planetary environments, cometary comae, and interstellar media. Despite decades of research, many aspects of their behavior remain poorly understood within a unified framework. While numerous theoretical and numerical models describe specific phenomena, such as dust charging, transport, waves, and self-organization, fully predictive models across the wide range of spatial and temporal scales in both laboratory and natural systems remain elusive. Conventional plasma descriptions rely on coupled differential equations for particle densities, momenta, and energies, but their solutions are often limited by computational cost, numerical uncertainties, and incomplete knowledge of boundary conditions and transport processes. Recent advances in machine learning (ML), particularly deep neural networks, offer new opportunities to complement traditional physics-based modeling. Here we review ML and artificial intelligence (AI) approaches, termed bottom-up data-driven methods, for dusty plasma research. Central to this effort is Dust Neural nEtworks Technology (DustNET), a community-driven dataset initiative inspired by ImageNet, integrating experimental, simulation, and synthetic data to enable predictive modeling, uncertainty quantification, and multi-scale analysis. DustNET-trained models may also be deployed in real-time experimental settings under edge computing constraints. Combined with emerging multi-modal AI foundation models and autonomous agents, this framework provides a pathway toward a unified, physics-informed understanding of dusty plasmas across laboratory, industrial, space, and astrophysical environments.

Previous experiments conducted in the Magnetized Dusty Plasma eXperiment revealed an intriguing phenomenon first referred to as imposed ordering. This occurs when micrometer-sized dust particles become aligned with the geometry of a conducting mesh placed above the dust (at a distance much larger than the plasma Debye length or the ion-neutral or electron-neutral mean free paths) in the presence of a strong magnetic field perpendicular to the mesh. In this work, results of a transition experiment are presented wherein starting from a classical two-dimensional Coulomb crystal with hexagonal symmetry in an unmagnetized plasma ( B=0 T), dust transitions to a state in which it flows along the geometry of a conducting mesh placed above it, mapping out the fourfold symmetry of the boundary condition. It is hypothesized that beyond a certain magnetization, elongated electric potential structures emanating from the mesh grow strong enough to drive the dust motion to reflect the mesh morphology, gradually transitioning from a sixfold self-ordering to fourfold imposed ordering. The various dust phases are quantified, and a critical value of magnetic field is identified in the transition experiment, indicating the onset of imposed ordering over the whole dust cloud.

Nanoparticles grow cyclically in non-thermal plasma from reactive precursor gases. The growth cycle is a process where the particles nucleate and grow until they are too big to remain confined in the plasma and move away from it, followed by a new generation of particle growth [1]. The growth cycle can be measured from intensity variation of the optical emission spectroscopy of the background plasma. For example, we measured the intensity variation of argon (Ar) I at 763.5 nm in various dusty plasma experiments to extract the particle growth cycle [2]. Recently, we found that the presence of a magnetic field decreases the growth cycle time [3]. Further studies revealed that the cycle time tends to exhibit a minimum around the onset of electron magnetization [4]. Additionally, a number of plasma parameters, such as intensity of optical emission spectroscopy electrode dc-self bias, and background plasma parameters such as electron temperature and electron density, also undergo transformations that coincide with the threshold for electron magnetization [5]. It is proposed that the changes in the plasma modify the force balance that suspends nanoparticles. This, in turn modifies the final size and growth rate of the nanoparticles.

Mapping individual components of the electric field, E, with high spatial resolution around the plasma sheath remains challenging, as most in situ plasma probes are generally too intrusive for reliable plasma potential measurements. An optically trapped micron-sized particle in a plasma environment represents the smallest, nonintrusive, or minimally intrusive diagnostic tool because it causes minimal disturbance to the plasma environment in which it is suspended. These microparticles can be used to map the electric field in situ with high spatial resolution in a radio frequency (RF) plasma sheath region. In this study, we optically trapped micron-sized single particles and precisely transported a single trapped particle within the cylindrically symmetric capacitively coupled plasma (CCP), over a radial distance of similar to 0-15 mm, a 2400-fold displacement relative to the particle size, corresponding to a spatial resolution of tens of micrometers. We measured |E| and its spatial distributions in the examined range by analyzing the particle's trajectory in the plasma after the optical forces were turned off. The radial component of the electric field, |Er|, was measured at multiple locations parallel to the electrode at 6.7 Pa. The |Er| was strongest near the circular electrode edges, reaching 0.478 +/- 0.005 V mm-1, and decreased to 0.458 +/- 0.001 V mm-1 toward the center of the electrode. We reconstructed the radial plasma potential, yielding a center-to-edge potential decrease of 4.6 V over one centimeter. This Delta V is consistent with reported CCP trends of small mid-plane radial potential gradients and serves as the confining potential for dust crystal and dust cluster studies. These results highlight the use of optical trapping of a single particle as an in situ, nonintrusive microprobe for quantitative mapping of Er(r) and V(r) in RF plasmas.

The Jeans instability in a magnetized dusty plasma is considered a fundamental process in space, where magnetic fields are common. We investigate the Jeans instability in a magnetized dusty plasma using 1D and 2D particle-in-cell simulations, in which dust grains are treated as particles and the Poisson's equation for the corresponding gravitational and electrostatic potentials is solved in a self-consistent manner. We first confirm that when the magnitude of the dust cyclotron frequency is larger than the Jeans frequency, the Jeans instability is completely stabilized, and the PIC simulation of the stable case shows the existence of cyclotron harmonics in the dispersion relation as predicted by the kinetic linear theory. In unstable cases, we find that the linear growth obtained by the simulations and the fluid and kinetic linear theory are consistent with each other, showing that the linear growth rate decreases as the magnetic field becomes stronger. The magnetized Jeans instability is also qualitatively modified due to the gyromotion of dust grains: (1) a dipole-like structure is observed in phase space and the density peak at the bottom of the gravitational potential is 3 times larger than the nonmagnetized case in the 1D simulation; and (2) dust grains form a filament, which corresponds to the direction in which the gyrating dust grains are accelerated by the gravitational potential, during the linear stage of the instability in the 2D simulation while dust grains condensate at a point in the nonmagnetized case.

We investigate static and dynamic behaviors of experimentally realized strongly coupled two-dimensional finite clusters in a complex (dusty) plasma. Clusters, ranging in size from N (number of grains) = 1 to 50 are obtained using a highly precise control arm assembly BECAA (bidirectional electrode control arm assembly) [R. Kumar et al., Rev. Sci. Instrum. 95, 053503 (2024)], without any gaps and maintaining constant plasma discharge conditions. Crystalline (static) behavior of these clusters is characterized by the pair correlation function, shell structures,- and configurations, which are found to be in good agreement with simulation and previous experiments. The dynamic behavior of a cluster is quantified through recorded trajectories of individual grains and identification of their respective shells over time. Quantities such as angular rotation, intershell transitions and different regimes of mean-squared displacement (MSD) are highlighted to provide insights into the transition from individual to collective or bulk behavior of clusters. These transitions are typically studied via simulations due to significant challenges in controlling the number of grains in a complex plasma, whereas simulations allow easy adjustment of grain number. We have overcome this hurdle using BECAA and produced clusters with N = 1-50 systematically and investigated their structures and dynamic properties to understand the individual-to-continuum transition.

In the presence of gravity, the micron-sized charged dust particles in a complex (dusty) plasma are compressed into thin layers. However, under the microgravity conditions of the Plasma Kristall-4 (PK-4) experiment on the International Space Station (ISS), the particles fill the plasma, allowing us to investigate the properties of a three-dimensional (3D) multi-particle system. This paper examines the change in the spatial ordering and thermal state of the particle system created when dust particles are stopped by periodic oscillations of the electric field, known as polarity switching, in a dc glow discharge plasma. Data from the ISS is compared against experiments performed using a ground-based reference version of PK-4 and numerical simulations. Initial results show substantive differences in the velocity distribution functions between experiments on the ground and in microgravity. There are also differences in the motion of the dust cloud, in microgravity there is an expansion of the dust cloud at the application of polarity switching which is not seen in the ground-based experiments. It is proposed that the dust cloud in microgravity gains thermal energy at the application of polarity switching due to this expansion. Simulation results suggest that this may be due to a modification in the effective screening length of the dust at the onset of polarity switching, which arises from a configuration energy between the charged particles. Experimental measurements and simulations show that an extended time (much greater than the Epstein drag decay) is required to dissipate this energy.

The movement of objects, from satellites to the International Space Station, through the local geospace environment can significantly impact plasma conditions. These disturbances lead to the formation of wakes, which can interfere with measurements of electric potentials, electric fields, and even serve as a mechanism for generating waves and instabilities. The development of scaled laboratory studies can provide valuable insights for understanding satellite observations.

Our method measures electric fields in dilute plasmas non-perturbatively with Rydberg electromagnetically induced transparency in rubidium. We detect Stark shifts in fluorescence for spatial profiling.

Carbonaceous dusty nanoparticles spontaneously grow in nonthermal plasmas from a gas mixture of argon and acetylene. These particles levitate and grow within the bulk plasma for a duration known as the growth cycle (T_c), after which they gradually move away. In experiments operating at 500 milliTorr, the particles reach a maximum radius of approximately 250 nm for T_c ∼ 121 s. However, the introduction of weak magnetic fields reduces both the maximum radius and T_c. The modified electron Hall parameter (H_e'), which quantifies the degree of electron magnetization, increases linearly with the magnetic field strength, transitioning from unmagnetized electrons (H_e' < 1) to magnetized electrons (H_e' > 1). T_c gradually decreases to around 40 s until H_e' ∼ 1 at approximately 330 Gauss, after which it remains roughly constant for fields up to about 1020 Gauss. Additionally, with increasing magnetic field strength, the dust growth rate initially decreases to H_e' ∼ 1, then increases slightly again. These results demonstrate that the onset of electron magnetization at can control the growth of nanoparticles from chemical precursors in nonthermal plasmas, which is relevant for industrial applications.

This study compares the growth cycles and spatial distribution of dust cloud for titania and carbonaceous dusty nanoparticles in capacitively coupled radiofrequency plasmas, with and without the presence of a weak magnetic field of approximately 500 Gauss. Findings on cycle time, growth rate, and spatial distribution of dust cloud are discussed. The growth of nanoparticles in these plasmas is cyclic, with particles reaching their maximum size and subsequently moving out of the plasma, followed by the generation of a new particle growth cycle. The presence of the magnetic field speeds up the growth cycle in both plasma. The magnetic field also makes the spatial distribution of the two dust cloud different from each other. Langmuir probe measurement of the background plasma parameters such as electron temperature and floating potential reveal radial variations in floating potential but not electron temperature. Furthermore, the magnetic field changes the radial variation of floating potential. These measurements, however, are not sufficient to explain why the two dust clouds appear differently. It is possible that the differences occur due to a gradient in the radial distribution of the magnetic field.

In dusty plasma environments, the spontaneous growth of nanoparticles from reactive gases has been extensively studied for over three decades, primarily focusing on hydrocarbons and silicate particles. Here, we introduce the growth of titanium dioxide, a wide band gap semiconductor, as dusty plasma nanoparticles. The resultant particles exhibited a spherical morphology and reached a maximum homogeneous radius of 230 $\pm$ 17 nm after an elapsed time of 70 seconds. The particle grew linearly and the growth displayed a cyclic behavior; that is, upon reaching their maximum radius, the largest particles fell out of the plasma, and a new growth cycle immediately followed. The particles were collected after being grown for different amounts of time and imaged using scanning electron microscopy. Further characterization was carried out using energy dispersive X-ray spectroscopy, X-ray diffraction and Raman spectroscopy to elucidate the chemical composition and crystalline properties of the maximally sized particles. Initially, the as-grown particles after 70 seconds exhibited an amorphous structure. However, annealing treatments at temperatures of 400 $^\circ$C and 800 $^\circ$C induced crystallization, yielding anatase and rutile phases, respectively. Notably, annealing at 600 $^\circ$C resulted in a mixed phase of anatase and rutile. These findings open new avenues for a rapid and controlled growth technique of titanium dioxide as dusty plasma.

We report a Bidirectional Electrode Control Arm Assembly (BECAA) for precisely manipulating dust clouds levitated above the powered electrode in RF plasmas. The reported techniques allow the creation of perfectly 2D dust layers by eliminating off-plane particles by moving the electrode from outside the plasma chamber without altering the plasma conditions. The tilting and moving of electrodes using BECAA also allows the precise and repeatable elimination of dust particles one by one to achieve any desired number of grains N without trial and error. Simultaneously acquired top and side view images of dust clusters show that they are perfectly planar or 2D. A demonstration of clusters with N = 1-28 without changing the plasma conditions is presented to show the utility of BECAA for complex plasma and statistical physics experimental design. Demonstration videos and 3D printable part files are available for easy reproduction and adaptation of this new method to repeatably produce 2D clusters in existing RF plasma chambers.

Experimental research into the control of particle charge in dusty plasmas conducted at Auburn University indicates that photocurrents generated by exposing dust to intense, near-ultraviolet light can provide a reliable and novel method of independently controlling dust charge without radically altering the background plasma; the experiment also showed that some particles may respond differently to this photo-discharge, with some exhibiting highly periodic responses to the discharge and others exhibiting chaotic behaviour. Since the dust particles in the experiment were a polydisperse sample of different sizes and shapes, particle geometry may play a role in explaining this difference. Simulations of particle discharge and dynamics are used in an attempt to reproduce experimental results and investigate a possible correlation between particle symmetry and dynamic periodicity.

We report the experimental realization of optical trapping and controlled manipulations of single particles of arbitrary properties, e.g., nano- to micrometer in size, transparent spheres to strongly light absorbing nonspherical particles, in low-pressure rf plasmas. First, we show optical trapping and transport of single particles in an unmagnetized rf plasma. Then, we show similar observations in a weakly magnetized rf plasma. This is the first demonstration of actively transporting (pushing and pulling) light-absorbing, nonspherical single particles in plasmas. The result suggests that optically trapped, actively controlled, single plasma dust particles (not limited to those externally sampled spheres) could be an in situ micro-probe for dusty plasma and magnetized dusty plasma diagnostics.

Pattern formation and self-organization in many biological and non-biological systems can be explained through Turing’s activator-inhibitor model. Here we show how this model can be employed to describe the formation of filamentary structures in a low-pressure electric discharge exposed to a strong magnetic field. Theoretical investigation reveals that the fluid equations describing a magnetized plasma can be rearranged to take the mathematical form of Turing’s activator-inhibitor model. Numerical simulations based on the equations derived from this approach could reproduce the various patterns observed in the experiments. Also, it is shown that a density imbalance between electrons and ions exists in the bulk of the magnetized plasma that generates an electric field structure transverse to the applied magnetic field. This electric field is responsible for the stability of the filamentary patterns in the magnetized plasma over time scales much longer than the characteristic time scales of the electric discharge.

The presence of solid, charged particulate matter in plasmas, i.e., so-called “dusty” or “complex” plasmas, has been the subject of researchers for several decades. Since the earliest considerations of these systems, from the observations of dust in comet tails, the investigations of the planetary rings of the outer planets of the solar system, and the transport of dust on airless bodies such as the moon and meteors, there has been a basic understanding of the potential coupling between a background plasma and charged dust particles. With the first observations of dust formation in processing experiments and the start of dedicated laboratory studies of the properties of dusty plasmas starting in the early 1990’s, it became possible to perform detailed investigations of the interactions between the dust particles and the plasma. As the capabilities of laboratory studies have continued to mature, experimental devices such as the Magnetized Dusty Plasma Experiment (MDPX) at Auburn University [1] have been able to provide a flexible, multi-user research platform that can explore a wide variety of dusty plasma phenomena with and without magnetic fields that can be scaled to support research questions from fusion to space plasma investigations.

Particles can spontaneously grow from reactive gases in a plasma to form dust. Over the past few years, several studies have focused on the growth of hydrocarbons and silicates from reactive gases such as acetylene and silane in argon plasmas. Here, we report for the first time the growth of titanium dioxide $(\text{TiO}_{2})$ dusty microparticles in a capacitively coupled rf plasma. The particles are spherical and grow up to a maximum diameter of 500 nm. The particle growth is cyclic. When they reach a critical radius, gravity becomes the dominant force on the particles and the particles fall out of the plasma. The collected particles are imaged via optical microscopy. The as-grown particles are amorphous. However, when air annealed at $500^{\circ}\mathrm{C}$ , they crystalize into anatase and gradually transform into rutile when annealed at higher temperature. X-ray diffraction and Raman spectroscopy are used to characterize the crystalline and chemical properties of the particles. We discovered that the base pressure of the particle growth chamber affects the morphology, size, cycle time, and temperature required for crystallization. We will present results for $\text{TiO}_{2}$ growth with base pressure varying from 1 - 10 millitorr. This presentation will discuss the evolution of the particle morphology as a function of particle growth time and plasma conditions. We will also show that gas “contamination” (i.e., initiating particle growth at a high initial base pressure), strongly influences the final structure of the titanium dioxide particles after annealing. The experiments and results presented here will pave the way for studies on new materials growth, besides hydrocarbons and silicates, in a dusty plasma.

Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles with sizes ranging from a few nanometers to a few micrometers. These media can be found in many natural environments as well as in various laboratory setups and industrial applications. As a separate branch of plasma physics, the field of dusty plasma physics was born in the beginning of 1990s at the intersection of the interests of the communities investigating astrophysical and technological plasmas. An additional boost to the development of the field was given by the discovery of plasma crystals leading to a series of microgravity experiments of which the purpose was to investigate generic phenomena in condensed matter physics using strongly coupled complex (dusty) plasmas as model systems. Finally, the field has gained an increasing amount of attention due to its inevitable connection to the development of novel applications ranging from the synthesis of functional nanoparticles to nuclear fusion and from particle sensing and diagnostics to nano-contamination control. The purpose of the present perspectives paper is to identify promising new developments and research directions for the field. As such, dusty plasmas are considered in their entire variety: from classical low-pressure noble-gas dusty discharges to atmospheric pressure plasmas with aerosols and from rarefied astrophysical plasmas to dense plasmas in nuclear fusion devices. Both fundamental and application aspects are covered.