  Structure wakefield acceleration (SWFA) is well suited for the linear
collider (LC) application due to its natural ability to accelerate positrons
and preserve emittance. Under the SWFA roadmap, which was developed in response
to Snowmass 2013 recommendations, four principal technologies: drive beam, main
beam, wakefield structure, and LC facility design, have been investigated. The
two SWFA schemes under development are the collinear wakefield accelerator
(CWA), in which the drive and main beam follow the same path through a
structure, and the two-beam accelerator (TBA), where the drive and main beam
pass through different structures. To further advance the SWFA technology in
the next decade, continuous and coordinated efforts must be carried out in a
more synchronized way. This whitepaper is written to address the research needs
in SWFA for preparation of Snowmass 2022.
