Shiltsev, V.D. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-TUPOB07 English 493-496 TUPOB07 ion collider luminosity plasma hadron Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-TUPOB07 https://jacow.org/napac2016/papers/tupob07.pdf The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosiity and feasibility of cost. The talk will give on overview of all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC, etc) and discuss major challenges and accelerator R&D required to claim these machines feasible.