Windows on the Universe: The Era of Multi-Messenger Astrophysics (WoU-MMA), and Computational and Data-enabled Science and Engineering (CDS&E). Topically appropriate proposals may also be submitted to the Plasma Physics program in response to NSF Dear Colleague Letters such as Critical Aspects of Sustainability (CAS): Innovative Solutions to Sustainable Chemistry (CAS-SC). When permitted under an MOU between NSF and another funding agency or private foundation, NSF may share information from proposals submitted to this solicitation for consideration of joint funding, and may invite employees of such organizations to attend merit review panels as observers. MOUs of relevance to the Plasma Physics program presently exist with the Department of Energy/Office of Science, National Nuclear Security Administration, the Air Force Office of Scientific Research, the US-Israel Binational Science Foundation, the Czech Science Foundation, Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), and the Swiss National Science Foundation. Plasma Physics is a study of matter and physical systems whose intrinsic properties are governed by collective interactions of large ensembles of free charged particles. 99.9% of the visible Universe is thought to consist of plasmas. The underlying physics of the collective behavior in plasmas has applications to space physics and astrophysics, materials science, applied mathematics, fusion science, accelerator science, and many branches of engineering. The Plasma Physics program supports research that can be categorized by several broad, sometimes overlapping, sub-areas of the discipline, including: magnetized plasmas in the laboratory, space, and astrophysical environments; high energy density plasmas; low temperature plasmas; dusty, ultra-cold, and otherwise strongly coupled plasmas; non-neutral plasmas; and intense field-matter interaction in plasmas. The focus of the Plasma Physics program is to generate an understanding of the fundamental principles governing the physical behavior of a plasma via collective interactions of large ensembles of free charged particles, as well as to improve the basic understanding of the plasma state as needed for other areas of science and engineering. Principal Investigators (PIs) are encouraged to consider including specific efforts to increase diversity of the plasma physics community and broaden participation of under-represented groups in Science, Technology, Engineering, and Mathematics (STEM) as Broader Impacts of proposed work. Development of new undergraduate and graduate plasma physics curricula, or curricula enhancement to include plasma physics topics in other courses, at institutions lacking such coursework is similarly encouraged. NSF recognizes that some research projects within this Program may require more than three years to realize demonstrable research outcomes. For such projects, PIs are encouraged to consult the above Program Director to discuss the possibility of submitting a proposal of 4- or 5-year duration. Some Plasma Physics-related activities are supported primarily by other NSF Programs. Proposals focused on the physical properties of individual or a small number of atoms or molecules, or optical physics, should be directed to the Atomic, Molecular, and Optical Physics Program within the Division of Physics. Proposals focused on understanding astrophysical systems should be directed to the Division of Astronomical Sciences. Proposals focused on understanding the Geospace environment or the Sun-Earth interactions should be directed to an appropriate program within the Geospace Section of the Division of Atmospheric and Geospace Sciences. Proposals focused on development of new materials using plasmas should be directed to an appropriate program in the Division of Materials Research. Proposals focused on plasma-assisted manufacturing should be directed to the Division of Civil, Mechanical and Manufacturing Innovation. Finally, proposals focused on use of plasmas for environmental and reaction engineering, environmental sustainability, combustion systems, or engineering of biomedical systems should be directed to an appropriate program within the Division of Chemical, Bioengineering, Environmental and Transport systems.