1. Diagnosis of Pellet Induced Bootstrap Current with Alfvén Cascades
B. Böse, E. Edlund
Alfven cascades have been observed numerous times on C-Mod
Modeling of their frequency response to changes in the q-profile is well established
Two ingredients needed: reversed shear q profiles and a fast ion population
Low density, low Zeff, high RF power are ideal for cascade excitation

2. Pellet Injection and Reverse Shear Q-profile
Shot:
ICRH during, or immediately after, Lithium pellet injection can induce a high confinement mode, PEP mode, which is characterized by reverse shear Q-profiles.
Shot:
J and q are taken from e-fit reconstructions
Pellet enters plasma
Plasma in PEP mode

3. Proposal for further studies
Use low density target discharge with nel ~ m-3
Pellet injection will be used to peak the density profile creating a large pressure gradient and hence a significant off axis bootstrap current
ICRF (> 3MW) heating through the pellet injection to generate a fast ion population
Reversed shear and fast ions may generate Alfven cascades
PCI will be used to look for core chirping modes from which some characteristics of the q-profile can be measured