Observation of Odd Toroidal Alfvén Eigenmodes

The existence of odd toroidicity induced Alfvén eigenmodes (TAE), from the coexistence of even and odd TAEs in a magnetic shear plasma, was reported. The reasons for the rare observations of odd TAEs in tokamak devices were also discussed. The odd TAEs were found to be excited due to the creation of a central low magnetic shear region by lower hybrid current drive (LHCD). The ion cyclotron range of frequency heating (ICRH) was deposited away from the plasma center, which also aided the fast particle drive for the odd TAEs.