FR2.2 – Particle (nm, Mm)-plasma interactions from lab to space
Challenge: To understand how the presence of growing nanometer to micrometer-sized solid particles in plasmas can be used to modify LTP for both industrial and space applications.
FR2.2(a) Nanoparticle growth in LTP
Background: Studies of silica-based (UAB)23 and carbon-based (AU)24 nanoparticles have investigated various hydrocarbon gas mixtures (e.g., CH4) and metal-based compounds. Extending the range of technologically relevant materials that could be controlled in magnetized plasmas (e.g., metal oxides for biomedical applications in TT3) also creates an opportunity to study particle formation in simulated, metalrich, astrophysical molecular clouds. This may give insights into the microprocesses that seed events such as planet formation.
Proposed research: To use hydrocarbon and metal-oxide based reactive gas mixtures in argon-nitrogen plasmas at high magnetic field (B ≥ 1 T) to study the structural and chemical properties of grown nanoparticles. This project is closely linked to FR2.4(a) on modeling and controlling particle charging processes.
- Studies of the formation of nano-dusty plasmas will first be performed using unmagnetized plasmas in a test stand. Facilities at AU and UAB will investigate nanoparticle formation in reactive plasma focusing on the development of techniques to remotely (e.g., emission spectroscopy, plasma
inductance) monitor and control the reactive plasma chemistry. (TT1, TT2, TT3) - Characterization of material properties will use microscopy (e.g., SEM, TEM) and spectroscopic (FTIR, Raman, etc.) diagnostic capabilities at AU, UAB, and TU.
FR2.2(b) Nanoparticle effects on space plasmas
Background: Recent technical advances of space observation instruments and observations by spacecraft (e.g., STEREO, Cassini, and Parker Solar Probe) have shown the ubiquitous existence of nanometer- to micrometer-sized dust in space plasmas. Furthermore, the presence of dust is believed to be associated with interplanetary field enhancements (IFEs), which are large-scale interplanetary magnetic field (IMF) structures characterized by a cusp-shaped enhancement in the field strength25.
Proposed research: We will investigate dust-plasma interaction in space plasmas using hybrid simulations, supported by laboratory studies, to determine if charged dust particles can contribute to a redistribution of solar wind momentum and energy.
- Space observations and modeling: i) a baseline distribution of micron–sized dust at one astronomical unit (1AU) will be determined observationally using all available data sets and techniques [e.g., Magnetospheric Multiscale (MMS) mission Acceleration Measurement System (AMS) and Electric Field (FIELDS) instruments, Solar Terrestrial Relations Observatory (STEREO) mission Radio Plasma Wave Investigation (S/WAVES), the Wind Radio Plasma Wave Investigation (WAVES), and the James Webb Space Telescope (JWST); (ii) distribution of micron–sized dust at 1AU will be simulated using a full Monte Carlo–based electrically-charged dust grain, electromagnetic solar wind, and radiation pressure model; and (iii) dynamics of dusty plasma will be modeled and quantified using a fully kinetic simulation approach.
- Laboratory studies: Injected monodisperse and polydisperse microparticles as well as grown nanoparticles in magnetized plasmas will be used to study dust-modified plasma instabilities in scaled space plasma conditions as indicated in Table 2.
Integration with Transformational Technology: These projects will support TT1, TT2, TT3, and TT5 by providing critical data on the interaction between the plasma and nanoparticles, including the spatial and 43 temporal modifications of the plasma density or potential that may impact the control over the plasma environment.
Impact: Dust particles are an important source of contamination in many plasma systems and their controlled formation has become an important commodity in industrial plasmas and a critical feature of many geospace and astrophysical plasmas. Validation: will be performed by investigating two aspects: 1) using multi-physics simulations (e.g., CFD-ACE+) to understand how particle growth can be influenced by different source gases and magnetic fields and 2) using fluid and hybrid simulations of nanoparticles to understand how interactions between the dust, ion and electrons in plasma, may be responsible for the redistribution of momentum and energy in lab (TT1 – 3), and solar system plasmas (TT5). Scaling: will use comparisons of nano- and micro-particle dust in ground and reduced-gravity/microgravity laboratory experiments; notably ion-dust coupling in both magnetized and unmagnetized systems that have flowing dust and large volume dust systems where the dust particles may represent a high fraction of the total plasma charge. Measurement: Spectroscopy will be used to characterize the plasma response and high-speed imaging techniques (>100 frames/sec) to identify the response of the dust particles.