Application of $$\hbox {GK}^{{\mathbf {1}}} \Sigma ^{+}_{\mathbf {g}}$$, $$\nu ' = 0 \rightarrow \hbox {B}^{1} \Sigma ^{+}_{\mathbf {u}}$$, $$\nu '' = 0$$ hydrogen band for the axial temperature measurement in the cathode sheath region of an abnormal glow discharge