TiPToP - TaIlored Pulse excitation for TailOred Plasma chemistries

等离子体技术已经成为当今许多价值数十亿英镑的行业的关键组成部分，如微处理器的纳米制造、节能照明、太阳能电池的生产和先进功能涂层的沉积。支撑这些基本技术有效性的是等离子体内部创造的独特的非平衡环境；包括反应性中性粒子、离子和高能电子的混合物。许多应用依赖于等离子体中产生的物质混合物和样品表面之间的协同相互作用；然而，等离子体科学的基本挑战之一是调整反应性等离子体物种的混合物，使它们对目标具有所需的效果。换句话说，等离子体化学的详细控制对于等离子体应用的成功至关重要，无论是现有的还是新兴的。这些等离子体中的化学反应主要由电子控制；更准确地说，是电子的能量分布。不同的电子能量分布函数（EEDF）驱动等离子体化学的差异，从而导致在表面上观察到的效应，使得EEDF，特别是对EEDF的控制至关重要。在传统的低压等离子体应用中，通过多频率施加电压或磁场来定制EEDF已被证明是等离子体化学控制的可行方法。然而，在快速发展的大气压等离子体（APP）科学领域，情况并非如此。等离子体在更高的压力下产生（在露天），这意味着等离子体粒子之间有更多的碰撞，严重阻碍了现有的低压EEDF控制方法。鉴于许多APP应用都依赖于等离子体化学，建立一种可行的技术来控制EEDF是一个比低压系统更紧迫的挑战。这一努力的成功将对整个应用领域产生深远影响，其中包括高价值材料加工、可再生化学和医疗保健技术等活动。在这项提案中，我们汇集了约克大学和利物浦大学在最先进的脉冲功率技术，最新的等离子体诊断技术和新颖的多尺度数值模拟方面的专业知识，以解决大气压等离子体等离子体化学控制的挑战。我们的目标是开发一种非常灵活的高压脉冲电源技术，其中脉冲特性，如上升时间，持续时间和重复率可以由用户改变。有了这种灵活性，放电的电激励可以用来修改EEDF，从而控制和定制APP的等离子体化学。复杂的等离子体诊断和数值模拟将使我们能够了解不同脉冲形状下观察到的化学变化的基本机制，从而为大气压等离子体技术带来新的能力：灵活的，定制的等离子体化学。这将是国际上第一次，在不改变背景气体或等离子体源设计的情况下，提供用户控制的定义良好的等离子体化学可调性。

Plasma technologies already form a key part of many of today's multi-billion pound industries such as the nanoscale fabrication of microprocessors, energy efficient lighting, production of solar cells and the deposition of advanced functional coatings. Underpinning the effectiveness of these essential technologies is the unique non-equilibrium environment created within the plasma; including a mix of reactive neutral particles, ions and energetic electrons. Many applications rely on the synergistic interaction between the mix of species created in the plasma and a sample surface; however one of the fundamental challenges in plasma science is tailoring the mixture of reactive plasma species such that they have the desired effect on a target.In other words, detailed control of the plasma chemistry is essential for success in plasma-enabled applications, both existing and emerging. The chemistry in these plasmas is largely controlled by the electrons; more precisely the distribution of energies that the electrons have. Different electron energy distribution functions (EEDF) drive differences in the plasma chemistry and therefore in the observed effect on a surface, making the EEDF, and especially control over the EEDF of key importance. In traditional low-pressure plasma applications, tailoring of the EEDF through e.g. multi-frequency applied voltages or magnetic fields, has proven to be a viable method for plasma chemistry control. However, the same cannot be said in the fast emerging field of atmospheric-pressure plasma (APP) science. Where plasmas are generated at much higher pressure (in open air), meaning there are many more collisions between plasma particles, severely hindering existing low-pressure EEDF control methods. Given the reliance on plasma chemistry in many APP applications, establishing a viable technique to control the EEDF is an even more pressing challenge than in low-pressure systems. Success in this endeavour would have a profound impact across the entire application space of APPs, which includes activities such as high-value materials processing, renewable chemistry and healthcare technologies.In this proposal, we bring together expertise from the University of York and the University of Liverpool in state-of-the-art pulsed power technology, the latest plasma diagnostic techniques and novel multiscale numerical modelling to address the challenge of plasma chemistry control for atmospheric-pressure plasmas. We aim to develop an extremely agile high-voltage pulsed power technology, in which pulse characteristics such as rise time, duration and repetition rate can be varied by the user. With this flexibility, the electrical excitation of the discharge can be used to modify the EEDF and therefore control and tailor the plasma chemistry of the APP. Sophisticated plasma diagnostics and numerical modelling will enable us to understand the underpinning mechanisms of the observed changes in chemistry for different pulse shapes, leading to a new capability for atmospheric-pressure plasma technologies: flexible, tailored plasma chemistry. This would be an international first and deliver user-controlled tunability of well-defined plasma chemistries without changing background gas or plasma source design.