Hardware requirements for 10Gbps line rate packet processing
This work (to both send and capture) is already well detailed and readily available.  

Intel have a full demo available with all the code and support.

Of course you could simply buy an Intel 10Gbps interface for about $300 and use a conventional PC (i7 with PCIe 3.0) with lots of DRam or a disk array to do your captures.
If you intend to do inline packet processing then you are probably best to use a very large memory configuration (128GB) and set aside 100GB as a Ram disk. this way you can process and move data using simple mem-cpy or mem-map to move data.