First, to obtain a runaway electron beam, the plasma current is ramped up to 1200 kA, followed by firing of an Ar killer pellet which induces a disruption, resulting in the generation of the REs during the current quench. While keeping the RE beam vertically centered, the plasma current which is composed primarily of the REs, is ramped up to and maintained close at 600 kA (q(a) ~ 6). The two scans to (a) achieve lower q(a) and (b) apply 3DMPs are carried out in this RE plateau. The target density will be maintained below 5e10^19 m^-3 for best measurements with the RIP diagnostic. Other key diagnostics include standard magnetics to measure magnetic fluctuations, and a fast camera to visualize RE structure with synchrotron emission. Lower q(a) values, like previous experiments, are obtained by compressing the RE beam at the DIII-D center-post (CP) during the RE plateau. The CP-scan will lower q(a) and hold them steady at values of 2, 3, 4, and 5. From the past experience, achieving and holding steady at lower q(a) can be challenging, and therefore developmental shots are planned. The second phase of the experiment we will apply n = 1 stationary and rotating 3DMPs. 3DMP amplitude and phase scan will be done, ideally starting with the lowest q(a) in the RE plateau. If CP-compression + 3DMP application consumes too much shot duration, then 3DMP will be applied by itself only.