For 10 points, identify this process that, in atoms, typically leaves behind a nucleus with excess positive charge.
The Keldysh parameter quantifies partly how likely this process is to occur as a consequence of tunneling. The degree to which this condition predominates in a gas is given by the Saha equation, and this condition is dominant in and constitutive of plasmas. A common version of this process occurs when a photon interacts with an atomic electron at a frequency corresponding to the binding energy. For 10 points, identify this process that, in atoms, typically leaves behind a nucleus with excess positive charge.
The Keldysh parameter quantifies partly how likely this process is to occur as a consequence of tunneling.
ionization