The characteristic frequency associated with drift waves involving electron flow is given by ω ω ∗ ∗ = k ⊥ ⊥ ( − − k B T e e B 0 ∇ ∇ n 0 ) , where k ⊥ ⊥ is the wavenumber perpendicular to the pressure gradient of the plasma, k B is the Boltzmann constant, T e is the electron temperature, e is the elementary charge, B 0 is the background magnetic field and ∇ ∇ n 0 is the density gradient of the plasma.