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In this paper, we present data from experimental studies of the DC breakdown in ethanol vapour at low pressure as well as electrical and optical measurements of DC discharge parameters from low-current to high-current regimes. A Paschen curve and the corresponding distribution of emission intensities at low-current were recorded in the range of pd (pressure x electrode gap) from 0.10 Torr cm to 3.00 Torr cm, covering the region of Paschen minimum. Recorded axial profiles of emitted light from low-current discharge reveal that heavy particles make up a significant part in ethanol vapour breakdown in a wide range of values of pd i.e. E/N, for values E/N>3 kTd they become dominant. Also, we recorded volt-ampere characteristics at working conditions close to the minimum of the Paschen curve, together with spatial profiles of lowcurrent discharge. In the region of transition from normal to abnormal glow, sudden changes of the regime of operation were observed.

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The results covered in this paper provide breakdown data represented by Paschen curves for methanol, isopropanol and n-butanol, along with the corresponding axial profiles of emission in Townsend regime of the discharge and including the optical emission spectra. Paschen curves were recorded in the range of pd (pressure x electrode gap) from 0.10 to 3.00 Torr cm. The optical emission spectra (OES) are recorded for wavelength range from 300 to 900 nm, for discharges in all studied alcohols. The recorded spectra enabled identification of species that participate in these discharges. All three alcohols exhibit emission from excited radicals OH (at 306.4 nm), CH (at 431.2 nm) and Hα (at 656.4 nm) produced mostly in dissociative excitation by electrons. Recorded profiles of emission enabled us to identify conditions where processes induced by heavy particles (ions and fast neutrals) are dominant in inducing emission from the discharge.