Working Group Description The Plasma Diagnostics Working Group facilitates the sharing of plasma diagnostics expertise and resources across the various research groups and collaborations of the CPU2AL project. Working group members pool experience in a broad range of techniques and plasma environments. Currently used techniques within the project include optical emission spectroscopy, Langmuir and impedance probes, time-resolved imaging, laser-induced fluorescence, and light scattering methods, employed to characterize diverse plasma regimes ranging from space and atmospheric plasmas to low-pressure, laser-generated, microwave, and particulate-rich laboratory plasmas. Working group activities include monthly virtual meetings via Zoom and in-person meetings and reports during the CPU2AL retreats and annual meetings. Shared Resources Optical Emission Spectroscopy Electrical Probes Scattering Techniques Processing Applications