Speaker
Description
The interplay between space charge and collective beam instabilities is a central challenge for high-intensity circular accelerators. Understanding how space charge influences instability thresholds and coherent motion is essential for future high-power accelerator facilities. We present new experimental studies of collective beam dynamics in the Fermilab Recycler Ring using the Waker system, which applies controlled transverse kicks to simulate wakefields in intense proton beams. By systematically varying beam intensity and applied wake strength, these measurements enable controlled investigations of collective effects in the presence of space charge. Measurements include instability thresholds, coherent tune shifts, and head-tail amplification produced by externally applied wakefield kicks. Results obtained over a range of beam intensities and wake strengths are compared with analytical models to investigate the interplay between space charge and collective effects. These studies provide new experimental insight into beam stability limits in synchrotrons operating with significant space charge.