The 2012 Joint Varenna–Lausanne International Workshop on the theory of fusion plasmas was very fruitful. A broad variety of topics was addressed, covering turbulence, magnetohydrodynamics (MHD), edge physics, and radio frequency (RF) wave heating. Moreover, the scope of the meeting was extended this year to include the physics of materials and diagnostics for burning plasmas. This evolution reflects the complexity of problems at hand in fusion, some of them triggered by the construction of ITER and JT-60SA. Long-standing problems without immediate consequences have sometimes become an urgent matter in that context. One may refer to, for instance, the choice of plasma facing components or the design of control systems.Another characteristic of these workshops is the interplay between various domains of plasma physics. For instance, MHD modes are currently investigated with gyrokinetic codes, kinetic effects are included in MHD stability analysis more and more, and turbulence is now accounted for in wave propagation problems. This is proof of cross-fertilization and is certainly a healthy sign for our community.Finally, introducing some novelty in the programme does not prevent from us respecting old traditions. As usual, many presentations were dedicated to numerical simulations. Combining advanced numerical techniques with elaborated analytical theory is certainly a trademark of the Varenna–Lausanne Workshop, which was respected again this year.The quality and size of the scientific output from this workshop is shown in this special issue of Plasma Physics and Controlled Fusion; a further 26 papers have already appeared in Journal of Physics: Conference Series in December 2012. We hope the readers will enjoy this special issue, and find therein knowledge and inspiration.
15th Workshop on MHD Stability Control: 3D Magnetic Field Effects in MHD Control