Towards a PWFA linear collider — opportunities and challenges

I discuss some key opportunities and challenges of a PWFA collider, and outline some objectives which I consider important to be able to assess the machine performance, assuming that numerous technical challenges can be solved. The highlighted topics are purely the choices of this author. Several other articles in this issue are relevant for a collider design, and discuss challenges for different sub-systems of a collider, including the articles on the beam delivery system [1], drive-beam generation [2], and emittance preservation [3]. A more complete overview of agreed challenges and objectives can be found in international research roadmaps [4,5]. Here, we highlight in particular the option of a PWFA γγ collider.