The rotating wall machine: a device to study ideal and resistive magnetohydrodynamic stability under variable boundary conditions.

The rotating wall machine, a basic plasma physics experimental facility, has been constructed to study the role of electromagnetic boundary conditions on current-driven ideal and resistive magnetohydrodynamic instabilities, including differentially rotating conducting walls. The device, a screw pinch magnetic geometry with line-tied ends, is described. The plasma is generated by an array of 19 plasma guns that not only produce high density plasmas but can also be independently biased to allow spatial and temporal control of the current profile. The design and mechanical performance of the rotating wall as well as diagnostic capabilities and internal probes are discussed. Measurements from typical quiescent discharges show the plasma to be high β (≤p>2μ(0)/B(z)(2)), flowing, and well collimated. Internal probe measurements show that the plasma current profile can be controlled by the plasma gun array.

[1]  Masaaki Yamada,et al.  Magnetic Reconnection in Astrophysical and , 2009 .

[2]  Alfredo Portone,et al.  Progress in physics and control of the resistive wall mode in advanced tokamaks , 2008 .

[3]  G. Fiksel,et al.  Impurities, temperature and density in a miniature electrostatic plasma and current source , 1997 .

[4]  C. Hegna.  Stabilization of line tied resistive wall kink modes with rotating walls , 2004 .

[5]  C. Gimblett.  LETTER TO THE EDITOR: Stabilization of thin shell modes by a rotating secondary wall , 1989 .

[6]  A. M. Garofalo,et al.  Comprehensive control of resistive wall modes in DIII-D advanced tokamak plasmas , 2009 .

[7]  R. Gruber,et al.  MHD-limits to plasma confinement , 1984 .

[8]  T. Intrator,et al.  Coalescence of two magnetic flux ropes via collisional magnetic reconnection , 2005 .

[9]  M D Nornberg,et al.  Intermittent magnetic field excitation by a turbulent flow of liquid sodium. , 2006, Physical review letters.

[10]  J. P. Goedbloed,et al.  Instability of a pinch surrounded by a resistive wall , 1972 .

[11]  V. Shafranov.  The stability of a cylindrical gaseous conductor in a magnetic field , 1956 .

[12]  R. Betti,et al.  Stabilization of the resistive wall mode by flowing metal walls , 2001 .

[13]  M. Linton.  Dynamics of magnetic flux tubes in space and laboratory plasmas , 2006 .

[14]  D. A. Hannum,et al.  Observation of resistive and ferritic wall modes in a line-tied pinch. , 2008, Physical review letters.

[15]  Martin Schwarzschild,et al.  Some instabilities of a completely ionized plasma , 1954, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[16]  G Serianni,et al.  Active-feedback control of the magnetic boundary for magnetohydrodynamic stabilization of a fusion plasma. , 2006, Physical review letters.

[17]  D. A. Hannum,et al.  Onset and saturation of the kink instability in a current-carrying line-tied plasma. , 2005, Physical review letters.

[18]  J. Freidberg.  Ideal magnetohydrodynamic theory of magnetic fusion systems , 1982 .

[19]  T S Taylor,et al.  Sustained stabilization of the resistive-wall mode by plasma rotation in the DIII-D tokamak. , 2001, Physical review letters.

[20]  F. Milani,et al.  Feedback stabilization of multiple resistive wall modes. , 2004, Physical review letters.

[21]  J. Manickam,et al.  Advances in global MHD mode stabilization research on NSTX , 2010 .

[22]  R. Groebner,et al.  Resistive wall mode stabilization by slow plasma rotation in DIII-D tokamak discharges with balanced neutral beam injection , 2006 .

[23]  Stewart C. Prager,et al.  High current plasma electron emitter , 1995 .

[24]  C. Gimblett,et al.  A rotating shell and stabilization of the tokamak resistive wall mode , 2000 .

[25]  K. Tritz,et al.  Active stabilization of the resistive-wall mode in high-beta, low-rotation plasmas. , 2006, Physical review letters.

[26]  D. J. Hartog,et al.  An optical probe for local measurements of fast plasma ion dynamics , 1998 .