Publications

Thesis

Refer to warwick wrap for my thesis (exp. 2025).

First author papers

• Effects of deuterium-tritium mix on the growth rates of the magnetoacoustic cyclotron instability in magnetised fusion plasmas (here)

• Simulations of ion cyclotron emission from highly energetic fusion-born protons in future aneutronic deuterium-helium-3 plasmas (here)

• The consequences of tritium mix for simulated ion cyclotron emission spectra from deuterium-tritium plasmas (here)
  • Abstract : Measurements of ion cyclotron emission (ICE) are obtained from most large magnetically confined fusion (MCF) plasma experiments, and may be used in future to quantify properties of the fusion-born alpha-particle population in deuterium-tritium (DT) plasmas in ITER. ICE is driven by spatially localised, strongly non-Maxwellian, minority energetic ion populations which relax collectively under the magnetoacoustic cyclotron instability (MCI). ICE spectral peaks are typically observed at, near, or separated by, integer harmonics of the energetic ion cyclotron frequency. Here, for the first time, we study how simulated ICE spectra from DT plasmas vary with tritium concentration and compare with an observed JET DT ICE spectrum. We incorporate a population of thermal tritons, in addition to thermal deuterons and an energetic minority population of fusion-born alpha-particles, in simulations with the kinetic particle-in-cell (PIC) code EPOCH. This code has previously been used extensively for interpretation of ICE observations in terms of the self-consistent gyro-resolved collective Maxwell-Lorentz dynamics of tens of millions of simulation particles. Our simulation parameters are relevant to the ICE-generative outer midplane edge region of JET DT plasma 26148, which included 11% tritium. Quantifying the variation of simulated ICE power spectra with tritium concentration reveals that our simulation with 11% tritium concentration most accurately represents the observed ICE spectrum from this plasma. This outcome is encouraging for the diagnostic application of ICE to fusion plasmas containing two thermal ion species, including future DT plasmas.

  Recommended citation: Slade-Harajda, Tobias (2024). "The consequences of varying tritium mix for simulated ion cyclotron emission spectra from deuterium-tritium plasmas" *Nucl. Fusion*

• 4-page EPS paper (here)
  • Abstract : Measurements of ion cyclotron emission (ICE) from magnetically confined fusion (MCF) plasmas are helpful for understanding the physics of minority energetic ion populations therein. ICE is observed from both tokamak and stellarator plasmas, and is characterised by strongly suprathermal spectral peaks at frequencies corresponding to local cyclotron harmonics of energetic ion populations. The location of emitting ions in physical space is inferred from the local magnetic field strength from the cyclotron frequency spacing, and their velocity space distribution must incorporate a region of strong positive gradient to drive collective radiative instability. This has been found to be the magnetoacoustic cyclotron instability (MCI) in most cases. The MCI involves the resonant collective excitation of electromagnetic waves at or near the intersection of cyclotron harmonic modes with the fast Alfvén wave in frequency-wavenumber space. ICE has been observed from plasmas in most large magnetically confined fusion (MCF) facilities, where it can be used for diagnosing the velocity-space distributions of energetic ion populations. It has substantial further potential for deuterium-tritium (DT) plasmas in ITER. Here we therefore focus on analysis of the dependence of simulated ICE spectra on tritium mix in DT plasmas.

  Recommended citation: Slade-Harajda, Tobias (2023). "The consequences of varying tritium mix for simulated ion cyclotron emission spectra from deuterium-tritium plasmas" *The 49th European Conference on Plasma Physics (2023)* Bordeaux, France.

• Reflective piece for the JPPP (here)
  • Abstract : In the second issue of the Journal of PGR Pedagogic Practice, published for the academic year 2022-23, our PGR authors reflect on their experiences of teaching throughout the pandemic, and the lessons we can learn as we move into the post-pandemic world. Many of the articles in this issue address the challenges GTAs have been confronted with in their teaching and as a part of their wider identity as postgraduate researchers. Our authors address issues of engagement through online teaching, and the innovative methods they have adopted to facilitate learning. Others engage in the important work of decolonising the classroom, explore GTA identity and wellbeing, and draw on lessons from beyond the undergraduate classroom. Since the premier issue, interest in the JPPP has grown beyond our own institution, and we hope that future issues will continue to provide fresh perspectives on the wider experiences, interactions, and practices of PGR teachers within Higher Education.

  Recommended citation: Slade-Harajda, Tobias (2022). "The Development of Teaching, from Covid-19 to in-person Laboratory Sessions" Journal of PGR Pedagogic Practice.

ORCID id : 0000-0002-4993-0757

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