Laser induced sparks in atmospheric helium and helium mixtures, probbed with thomson scattering

Summary form only given. In the plasma community there is widespread interest in atmospheric plasmas as they have various applications such as medicine, surface treatment and lighting for example. Helium is a commonly used gas in such plasmas. Emission spectroscopy is usually used to obtain information about the plasma parameters1. However, most of the emission line studies rely on Stark broadening theories where self-absorption of lines can be an issue and result in incorrect values of n e . A diagnostic such as Thomson scattering can be used to test the reliability of emission based methods.