The annual workshop on MHD stability control has been held since 1996 with an emphasis on controlling MHD stability, which is considered to be an obstacle to achieving high performance in fusion reactors. The meeting is organized as a joint US/Japan undertaking with the meeting held in the US and Japan in alternating years. Each year, a specific theme is selected, based on the interest of our community, ranging from burning plasmas to fundamental physics processes essential for MHD stability. The 2009 meeting with the theme of 'Assuring successful MHD control in ITER' was held at the Princeton Plasma Physics Laboratory, Princeton University. With ITER construction progressing at full speed, there is increasing interest in assuring successful MHD control in ignited plasmas and beyond. Focusing on planned hardware and development of plasma profile control systems in ITER operational scenarios, subjects included instabilities such as sawteeth, fishbones and TAEs, NTMs, locked modes, RWMs, and ELMs. Control aspects included mode control, non-axis-symmetric error-field control, and disruption control in tokamaks, RFPs, and stellarators. In this special section of Plasma Physics and Controlled Fusion we present several of the invited and contributed papers from the 2009 workshop, which have been subject to the normal refereeing procedures of the journal. These papers give a sense of the exceptional quality of the presentations at this workshop, all of which may be found at http://fusion.gat.com/conferences/mhd09/ The program committee deeply appreciates the participation and support our community has shown for more than a decade in this workshop series. Without doubt, we will extend our workshop along with the progress of fusion research toward successful reactors.
Chapter 8: Plasma operation and control