\textbf{Dissimilar }$\beta $\textbf{ effect on electrostatic and electromagnetic turbulence in DIII-D H-mode plasmas}

The anomalous transport in existing tokamaks and stellerators is generally attributed to electrostatic turbulence. The electromagnetic turbulent transport mechanism is predicted to play an important role in future high $\beta $ (ratio of plasma pressure to magnetic pressure) fusion plasmas. It is essential to understand the $\beta $ effect on turbulence to test turbulence theory and simulations. A $\beta_{\mathrm{N}}$ (with $\beta _{\mathrm{N}}=\beta $/(I$_{\mathrm{p}}$/aB$_{\mathrm{T}}))$ ramp experiment was performed in DIII-D H-mode plasmas. It was observed that the internal magnetic turbulence measured by millimeter wave cross-polarization scattering increased with $\beta_{\mathrm{N\thinspace }}$while low-k \~{n} decreased, and intermediate-k \~{n} remained approximately constant. A decrease in electron thermal confinement time was also observed coinciding with the $\beta_{\mathrm{N\thinspace }}$ramp. These results indicate a decoupling of the density and magnetic fluctuations as well as an effect on electron thermal confinement which might be explained by magnetic fluctuations. Comparison with turbulence simulations will be reported.