Parametric Wave Coupling and Non-Linear Mixing in Plasma
Lead Research Organisation:
University of Strathclyde
Department Name: Physics
Abstract
Plasma is a state of matter that exists when the energy level or temperature become so high that electrons are no longer bound to atoms. This produces at least two species (negative electrons and positive ions) with opposite charge and very different masses (electron mass << ion mass). The charge of both types of particle make them each respond to electromagnetic fields (such as light, microwave and radio waves), but in opposite directions, and at very different rates. They particularly respond to waves at frequencies close those of natural plasma oscillations, determined by complicated combinations of the magnitude and direction of any static magnetic field, the number density and mass of the particles. They can absorb wave energy at frequencies called 'resonances', and reflect wave energy at frequencies called 'cut-offs'. These effects are often used to heat or measure plasmas in important laboratory experiments and applications, such as new techniques for energy production through fusion reactions (magnetically confined) and industrial processing as well as natural plasmas in the Earth's magnetosphere and ionosphere. Both natural ionospheric and magnetospheric plasmas are important to modern communication and navigation systems. In industrial processing, plasma physics underpins semiconductor processing and hence modern digital technology. In fusion energy research the impact potential is to enable an almost unlimited supply of energy, addressing serious environmental concerns surrounding the use of fossil fuel, with no long term radioactive byproducts.
Parametric coupling refers to a multi-wave interaction where two or more waves exchange energy when their frequencies are related by a natural plasma oscillation frequency. Such processes have recently been found to cause difficulties in laser-plasma interactions for inertial confinement fusion, whilst at the same time offering exciting potential for new and more flexible ways of delivering energy into both inertially and magnetically confined fusion plasmas. Indications exist that suggest such new techniques will be increasingly important as such research moves from fundamental experiments to application scale equipment. We therefore propose to undertake fundamental research investigating these interactions in the microwave frequency range. The microwave range is particularly appealing for such research since powerful sources and amplifiers, developed for a range of applications, are readily available, can be very precisely controlled, enhancing the ability to investigate the plasma physics dynamics, whilst groundbreaking research points towards microwave generators achieving very high levels of normalised intensity (a measure of the effective intensity of the wave, affected by the wavelength, meaning that microwave intensities are effectively 'uplifted' compared to optical intensities). This therefore indicates potential in the microwave frequency range to explore the dynamics of extreme ranges of wave-plasma interaction in the near future. The project will be based at the University of Strathclyde where it benefits from co-location within a pre-eminent microwave source research laboratory. A further motivation for investigating the effect of wave coupling using microwaves is its direct application relevance to industrial processing and magnetic confinement fusion plasma physics.
The coupling of two precisely controlled microwave beams (~10cm to 3cm wavelength) in a (weakly to strongly) magnetised helicon plasma by plasma (acoustic-like) oscillations in the electrons and ions, cyclotron oscillation of the electrons and ions and hybrid oscillations including both quasi-acoustic and cyclotron motion will be investigated, as will the effects of stochastic heating where 'quasi-random' motion of particles in high amplitude waves gives very rapid increase in effective temperature.
Parametric coupling refers to a multi-wave interaction where two or more waves exchange energy when their frequencies are related by a natural plasma oscillation frequency. Such processes have recently been found to cause difficulties in laser-plasma interactions for inertial confinement fusion, whilst at the same time offering exciting potential for new and more flexible ways of delivering energy into both inertially and magnetically confined fusion plasmas. Indications exist that suggest such new techniques will be increasingly important as such research moves from fundamental experiments to application scale equipment. We therefore propose to undertake fundamental research investigating these interactions in the microwave frequency range. The microwave range is particularly appealing for such research since powerful sources and amplifiers, developed for a range of applications, are readily available, can be very precisely controlled, enhancing the ability to investigate the plasma physics dynamics, whilst groundbreaking research points towards microwave generators achieving very high levels of normalised intensity (a measure of the effective intensity of the wave, affected by the wavelength, meaning that microwave intensities are effectively 'uplifted' compared to optical intensities). This therefore indicates potential in the microwave frequency range to explore the dynamics of extreme ranges of wave-plasma interaction in the near future. The project will be based at the University of Strathclyde where it benefits from co-location within a pre-eminent microwave source research laboratory. A further motivation for investigating the effect of wave coupling using microwaves is its direct application relevance to industrial processing and magnetic confinement fusion plasma physics.
The coupling of two precisely controlled microwave beams (~10cm to 3cm wavelength) in a (weakly to strongly) magnetised helicon plasma by plasma (acoustic-like) oscillations in the electrons and ions, cyclotron oscillation of the electrons and ions and hybrid oscillations including both quasi-acoustic and cyclotron motion will be investigated, as will the effects of stochastic heating where 'quasi-random' motion of particles in high amplitude waves gives very rapid increase in effective temperature.
Planned Impact
The impact of our research can be found primarily through the application of fundamental plasma science research on society, energy, environment, economy and policy.
A primary beneficiary of fundamental plasma science research and this proposed programme is both the inertial and magnetic confinement approaches to fusion energy. Realisation of practical schemes of fusion energy will result in a near limitless supply of energy with minimum environmental consequences, due to the high availability of the input materials and the relatively benign nature of the by-products. Affordable energy sources which do not contribute to the environmental problems associated with fossil fuels, or to the production of the long life radioactive by-products associated with fission energy, whilst avoiding the problems of proliferation, have profound, global sociological and economic benefits. Availability of energy is important in addressing social problems including equality and healthcare, whilst wide distribution of the necessary fusion input materials eliminates a source of competition and potential international tension. Ensuring an adequate energy supply in the face of declining fossil reserves (setting aside for the present environmental misgivings surrounding carbon emissions) is a key problem for government policy with enormous economic consequences. As such the impact of this research programme through its relevance to both mainstream approaches to fusion energy can be very substantial.
Research in the field of plasma science has potential for direct impact on industrial processing of materials. Low pressure industrial processing discharges need to achieve stable, dense and uniform plasma over a wide processing surface, and are usually produced by RF drive, often at two or more frequencies. The plasma source we plan to investigate, the helicon, is particularly attractive for future applications, as it is an effective and efficient approach to produce large volumes of highly ionised gas at relatively low pressures. Our research is on the interaction of a range of RF and microwave signals with plasma. We would anticipate being able to contribute to the understanding of multi-frequency industrial discharges. One of the most economically important industrial applications is in semiconductor processing. Enhancements in this field can have both direct impact on the economy and indirect impact via enhanced digital technology.
Our experience shows that research in plasma physics has further potential for economic impact through the UK high technology electronics industry. Plasma-wave interactions are relevant to 'free-electron' technology. Two of the project partners are industrial companies within this community. In addition to direct support of this specific project through the provision of key aspects of hardware, both firms sponsor and engage in knowledge exchange (KE) projects at Strathclyde building on prior fundamental plasma physics research. One potential impact of our project will be novel schemes for heating of magnetically confined fusion plasmas. One of our partners (TMD) is a leading UK designer and manufacturer of high power microwave sources and amplifiers whose sales have doubled in the last 5 years. They are well placed to take advantage of developments in novel heating schemes in fusion science, with the potential for new products and markets.
Strathclyde has a leading reputation for research in novel microwave sources and has a strong track record of KE with two of the leading UK-based manufacturers in the field of free-electron technology (e2v and TMD) which resulted in a highly ranked impact case study in the last REF. As an example of this type of impact, previous EPSRC fundamental research recently enabled Strathclyde (via the present PI Ronald) to form and lead a UK academic-industrial partnership (also featuring RAL and TMD) to secure international funding (from ESA) for research into space communication.
A primary beneficiary of fundamental plasma science research and this proposed programme is both the inertial and magnetic confinement approaches to fusion energy. Realisation of practical schemes of fusion energy will result in a near limitless supply of energy with minimum environmental consequences, due to the high availability of the input materials and the relatively benign nature of the by-products. Affordable energy sources which do not contribute to the environmental problems associated with fossil fuels, or to the production of the long life radioactive by-products associated with fission energy, whilst avoiding the problems of proliferation, have profound, global sociological and economic benefits. Availability of energy is important in addressing social problems including equality and healthcare, whilst wide distribution of the necessary fusion input materials eliminates a source of competition and potential international tension. Ensuring an adequate energy supply in the face of declining fossil reserves (setting aside for the present environmental misgivings surrounding carbon emissions) is a key problem for government policy with enormous economic consequences. As such the impact of this research programme through its relevance to both mainstream approaches to fusion energy can be very substantial.
Research in the field of plasma science has potential for direct impact on industrial processing of materials. Low pressure industrial processing discharges need to achieve stable, dense and uniform plasma over a wide processing surface, and are usually produced by RF drive, often at two or more frequencies. The plasma source we plan to investigate, the helicon, is particularly attractive for future applications, as it is an effective and efficient approach to produce large volumes of highly ionised gas at relatively low pressures. Our research is on the interaction of a range of RF and microwave signals with plasma. We would anticipate being able to contribute to the understanding of multi-frequency industrial discharges. One of the most economically important industrial applications is in semiconductor processing. Enhancements in this field can have both direct impact on the economy and indirect impact via enhanced digital technology.
Our experience shows that research in plasma physics has further potential for economic impact through the UK high technology electronics industry. Plasma-wave interactions are relevant to 'free-electron' technology. Two of the project partners are industrial companies within this community. In addition to direct support of this specific project through the provision of key aspects of hardware, both firms sponsor and engage in knowledge exchange (KE) projects at Strathclyde building on prior fundamental plasma physics research. One potential impact of our project will be novel schemes for heating of magnetically confined fusion plasmas. One of our partners (TMD) is a leading UK designer and manufacturer of high power microwave sources and amplifiers whose sales have doubled in the last 5 years. They are well placed to take advantage of developments in novel heating schemes in fusion science, with the potential for new products and markets.
Strathclyde has a leading reputation for research in novel microwave sources and has a strong track record of KE with two of the leading UK-based manufacturers in the field of free-electron technology (e2v and TMD) which resulted in a highly ranked impact case study in the last REF. As an example of this type of impact, previous EPSRC fundamental research recently enabled Strathclyde (via the present PI Ronald) to form and lead a UK academic-industrial partnership (also featuring RAL and TMD) to secure international funding (from ESA) for research into space communication.
Organisations
- University of Strathclyde (Lead Research Organisation)
- Rutherford Appleton Laboratory (Collaboration)
- University of St Andrews (Collaboration)
- WEST VIRGINIA UNIVERSITY (Collaboration)
- Russian Academy of Sciences (Collaboration)
- TMD Technologies (United Kingdom) (Project Partner)
- MBDA (United Kingdom) (Project Partner)
- CCFE/UKAEA (Project Partner)
Publications
Ronald K
(2017)
Laboratory experiments simulating electron cyclotron masers in space
in EPJ Web of Conferences
Shustin E
(2017)
Computer simulation of the sheath and the adjacent plasma in the presence of a plasma source
in Vacuum
Ronald K.
(2018)
Apparatus for investigating non-linear microwave interactions in magnetised plasma
in 45th EPS Conference on Plasma Physics, EPS 2018
Tarakanov V
(2019)
Simulation of sputtering from an isolated conductor surrounded by a dielectric during plasma etching
in Vacuum
Heelis T
(2019)
Large-scale numerical simulation of ionospheric Langmuir turbulence excited by a radio frequency electromagnetic wave
in Plasma Physics and Controlled Fusion
Speirs DC
(2019)
Development of a high-k RF scattering system for MAST-U
Speirs D
(2019)
Maser radiation from collisionless shocks: application to astrophysical jets
in High Power Laser Science and Engineering
Bingham R.;
(2019)
Acceleration of electrons and maser radiation from collisionless shocks
Robertson C
(2019)
71-76 GHz Folded Waveguide TWT for Satellite Communications
Yin H
(2019)
Compact high-power millimetre wave sources driven by pseudospark-sourced electron beams
in IET Microwaves, Antennas & Propagation
Trines RMGM
(2020)
New criteria for efficient Raman and Brillouin amplification of laser beams in plasma.
in Scientific reports
Nix L
(2020)
Demonstration of efficient beam-wave interaction for a MW-level 48 GHz gyroklystron amplifier
in Physics of Plasmas
Xie J
(2020)
Study of a 0.35 THz Extended Interaction Oscillator Driven by a Pseudospark-Sourced Sheet Electron Beam
in IEEE Transactions on Electron Devices
Varun
(2020)
PIC Simulation of Pseudospark Discharge-Based Plasma Cathode Electron Source for the Generation of High Current Density and Energetic Electron Beam
in IEEE Transactions on Electron Devices
MacLachlan A
(2020)
Excitation and coupling of volume and surface fields on complex electrodynamic surfaces at mm-wave and THz frequencies
in IET Microwaves, Antennas & Propagation
Eliasson B
(2020)
Observation of electron cyclotron harmonic emissions due to electrostatic instabilities in mirror-confined plasma
in Physical Review Research
Brandão B
(2021)
Bandwidth effects in stimulated Brillouin scattering driven by partially incoherent light
in Plasma Physics and Controlled Fusion
Stasiewicz K
(2021)
Local Acceleration of Protons to 100 keV in a Quasi-Parallel Bow Shock
in Journal of Geophysical Research: Space Physics
Bott AFA
(2021)
Time-resolved turbulent dynamo in a laser plasma.
in Proceedings of the National Academy of Sciences of the United States of America
Constable D
(2021)
Numerical and Experimental Validation of the Passive Performance of a Coharmonic Gyro-Multiplier Interaction Region
in IEEE Transactions on Microwave Theory and Techniques
Donaldson C
(2021)
Low-Loss Transmission Line for a 3.4-kW, 93-GHz Gyro-Traveling-Wave Amplifier
in IEEE Transactions on Electron Devices
Eliasson B
(2021)
Controlled beat-wave Brillouin scattering in the ionosphere.
in Nature communications
Arrowsmith C
(2021)
Generating ultradense pair beams using 400 GeV / c protons
in Physical Review Research
L Selman
(2021)
Selman L
Macinnes P
(2022)
Numerical Analysis of High-Power X -Band Sources, at Low Magnetic Confinement, for Use in a Multisource Array
in IEEE Transactions on Electron Devices
Stasiewicz K
(2023)
Electron heating mechanisms at quasi-perpendicular shocks - revisited with magnetospheric multiscale measurements
in Monthly Notices of the Royal Astronomical Society
| Description | The project is ongoing and these findings should be viewed as ongoing and preliminary. A novel scheme of lightweight magnet coils have been designed and manufactured as part of the apparatus design. These coils are potentially of wider interest beyond this project. Modern microwave amplifiers and oscillators have been assessed and in tested. These combined with suitable optics are capable of achieving normalised power levels well above those required to initiate a range of plasma instabilities. Numerical simulations have been developed for the excitation of Raman and electrostatic electron cyclotron waves in plasma by microwave beat-waves The apparatus has been operated at frequencies in the range 10-30MHz and at drive powers of up to 200W Measurements of the plasma by RF compensated Langmuir probes and microwave interference techniques show plasma densities and temperatures in the range intended |
| Exploitation Route | It is anticipated that this research will be of use to both magnetically and inertially confined fusion plasma researchers, and to researchers in materials processing. |
| Sectors | Electronics,Energy,Other |
| Description | Multiscale turbulent dynamics of tokamak plasmas |
| Amount | £4,349,473 (GBP) |
| Funding ID | EP/R034737/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2018 |
| End | 09/2023 |
| Title | Data for "Controlled beat-wave Brillouin scattering in the ionosphere" |
| Description | The dataset contains experimental data as well as simulation data used to analyse an ionospheric beat wave Brillouin scattering experiment experiment carried out at the EISCAT facility in Tromso, Northern Norway, 29 November 2014. More details on the data are given in the README file as well as in separate README files contained in each data file. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://pureportal.strath.ac.uk/en/datasets/d4ca75d2-a462-4940-9614-b1b3fe5a8e2e |
| Title | Data for Large-scale Numerical Simulation of Ionospheric Langmuir Turbulence Excited by a Radio Frequency Electromagnetic Wave |
| Description | "This dataset contains simulation data generated by the simulation of an ionospheric heating experiment described in the article ""Data for Large-scale Numerical Simulation of Ionospheric Langmuir Turbulence Excited by a Radio Frequency Electromagnetic Wave"" published in the journal ""Plasma Physics and Controlled Fusion"". The data consists of periodic snapshots in time of the simulation variables stored in hdf5 format. MATLAB scripts to read and analyze the data are also included. See the README file for a detailed description. " |
| Type Of Material | Database/Collection of data |
| Year Produced | 2018 |
| Provided To Others? | Yes |
| Impact | . |
| Title | Data for: "Observation of electron cyclotron harmonic emissions due to electrostatic instabilities in mirror-confined plasma" |
| Description | The dataset contains data and some Matlab scripts to analyze the data for wave electric fields from Vlasov simulations and dispersion diagrams and growth rates obtained by solving dispersion relations for electrostatic electron cyclotron instabilities in magnetized plasma. More details are given in the README file. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://pureportal.strath.ac.uk/en/datasets/45a4eb8b-4812-49ee-bf5e-1ba22b603690 |
| Description | Partnership on high frequency circuits and components |
| Organisation | Rutherford Appleton Laboratory |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Strathclyde have been involved in designing novel high frequency waveguides for many years, and in the measuring of these waveguides in both cold and hot tests. In the context of TDoTP Strathclyde (with York and others) are actively developing a new microwave diagnostic. We believe RAL Space expertise will be important in delivering this diagnostic. |
| Collaborator Contribution | RAL Space's precision machine shop have made critical contributions to the fabrication of the novel waverguides. They have expertise in high performance sources and detectors in the sub-mm wave range that will be vital for future microwave diagnostic developement. |
| Impact | There have been many successful outcomes from this partnership between Strathclyde and RAL Space in the past, including a world leading result in fast wave microwave amplifiers at W band. In the context though of the TDoTP project the outcomes are envisioned for the future. |
| Start Year | 2019 |
| Description | Research Collaboration on Microwave emission due to kinetic instabilities in an overdense mirror-confined plasma (supported by Royal Society in UK and RFBR in Russia) |
| Organisation | Russian Academy of Sciences |
| Department | Institute of Applied Physics |
| Country | Russian Federation |
| Sector | Academic/University |
| PI Contribution | Strathclyde are contributing the simulations of complex microwave emissions from overdense mirror confined and microwave driven plasma |
| Collaborator Contribution | IAP are undertaking experiments driving plasma in a mirror confined plasma volume using microwaves, studying the micorwave emissions |
| Impact | A joint conference paper has arisen from bilateral visits. |
| Start Year | 2018 |
| Description | Research collaboration with Prof. Mark Koepke, University of West Virginia, USA |
| Organisation | West Virginia University |
| Country | United States |
| Sector | Academic/University |
| PI Contribution | Host : Hosting academic visitor : Research collaborations during visits of Prof. Mark Koepke, University of West Virginia, USA to University of Strathclyde |
| Collaborator Contribution | Prof. Mark Koepke contributed his extensive expertise in plasma physics, especially in the interpretation of experimental results. |
| Impact | Several joint research publications in international refereed research journals with Prof. Mark Koepke as a co-author |
| Start Year | 2007 |
| Description | Research collaboration with Prof. R. Alan Cairns, University of St Andrews |
| Organisation | University of St Andrews |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | Host : Hosting academic visitor : Collaboration in plasma physics research with Prof. R. Alan Cairns of the University of St. Andrews |
| Collaborator Contribution | Prof. R. Alan Cairns contributed his theoretical plasma physics knowledge and expertise gained from over 40 years of active research. |
| Impact | Many joint research papers in refereed international research journals have been published with Prof. R. Alan Cairns as a co-author. Prof R. Alan Cairns has been appointed as a Visiting Professor to our research group at the University of Strathclyde. |
| Description | A magnetized plasma apparatus for non-linear microwave interaction experiments |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster presentation at the 71st GEC conference 2018 |
| Year(s) Of Engagement Activity | 2018 |
| Description | A magnetized plasma experiment to study non-linear microwave interactions |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster presentation at the 60th APS DPP Meeting |
| Year(s) Of Engagement Activity | 2018 |
| Description | An apparatus for investigating micorwave interactions in magnetized plasmas |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster paper at the 19th International Congress on Plasma Physics (ICPP) |
| Year(s) Of Engagement Activity | 2018 |
| Description | Design and measurement of a Penning discharge plasma |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster presentation at the 71st GEC 2018 |
| Year(s) Of Engagement Activity | 2018 |
| Description | Development of an apparatus to study nonlinear microwave coupling in magnetised plasma |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster paper at the 24th Europhysics Conference on the Atomic and Molecular Physics of Ionized Gases (ESCAMPIG) |
| Year(s) Of Engagement Activity | 2018 |
| Description | Experimental concept for investigating nonlinear microwave interactions in magnetised plasma |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster presentation at 45th IoP Annual Spring Plasma Physics Conference |
| Year(s) Of Engagement Activity | 2018 |
| Description | Laboratory Open Evening during ESCAMPIG 2018 conference (hosted at Glasgow University) |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | As part of the ESCAMPIG 2018 leading international practitioners were present in the city of Glasgow. An evening event was hosted where the visitors came to Strathclyde University and were able to review the facilities and research. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Magnetized plasma appartus for investigating non-linear interactions at microwave frequencies |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster paper at IEEE ICOPS 2018 conference |
| Year(s) Of Engagement Activity | 2018 |
| Description | Maser radiation from electrons accelerated by magnetised collisionless shock waves |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Poster presentation at 60th APS DPP conference |
| Year(s) Of Engagement Activity | 2018 |