We test using Lyman-α (Lyα) transmission spikes in synthetic, high-redshift Lyα forest quasar spectra constructed from hydrodynamical simulations to probe intergalactic gas residing in cosmological voids during cosmic reionization. We find a linear correlation with slope ~1 between spike and void widths. Lyα spike shapes correlate with the density and neutral hydrogen fraction of the intergalactic medium. They probe the central regions of voids and are hence a powerful tool to study the properties of cosmic voids and their gas contents.

Emmerich, Master's thesis, 2021

We investigate melamine formaldehyde microparticles injected into argon and neon DC plasmas. Due to electrical forces, the charged particles start moving along the electric field through the plasma volume. By determining the particle velocities, we estimate the microparticle charge to test their agreement with the orbit motion limited (OML) theory. The measured charges vary by a factor of ~4 compared to the OML theory, although the correlation to the gas pressure is as predicted.

Emmerich, Bachelor's thesis, 2017