TY - JOUR

T1 - Tomography of fast-ion velocity-space distributions from synthetic CTS and FIDA measurements

A1 - Salewski,Mirko

A1 - Geiger,B.

A1 - Nielsen,Stefan Kragh

A1 - Bindslev,Henrik

A1 - Garcia-munoz,M.

A1 - Heidbrink,W.W.

A1 - Korsholm,Søren Bang

A1 - Leipold,Frank

A1 - Meo,Fernando

A1 - Michelsen,Poul

A1 - Moseev,D.

A1 - Stejner Pedersen,Morten

A1 - Tardini,G.

AU - Salewski,Mirko

AU - Geiger,B.

AU - Nielsen,Stefan Kragh

AU - Bindslev,Henrik

AU - Garcia-munoz,M.

AU - Heidbrink,W.W.

AU - Korsholm,Søren Bang

AU - Leipold,Frank

AU - Meo,Fernando

AU - Michelsen,Poul

AU - Moseev,D.

AU - Stejner Pedersen,Morten

AU - Tardini,G.

PB - Institute of Physics Publishing

PY - 2012

Y1 - 2012

N2 - We compute tomographies of 2D fast-ion velocity distribution functions from synthetic collective Thomson scattering (CTS) and fast-ion D (FIDA) 1D measurements using a new reconstruction prescription. Contradicting conventional wisdom we demonstrate that one single 1D CTS or FIDA view suffices to compute accurate tomographies of arbitrary 2D functions under idealized conditions. Under simulated experimental conditions, single-view tomographies do not resemble the original fast-ion velocity distribution functions but nevertheless show their coarsest features. For CTS or FIDA systems with many simultaneous views on the same measurement volume, the resemblance improves with the number of available views, even if the resolution in each view is varied inversely proportional to the number of views, so that the total number of measurements in all views is the same. With a realistic four-view system, tomographies of a beam ion velocity distribution function at ASDEX Upgrade reproduce the general shape of the function and the location of the maxima at full and half injection energy of the beam ions. By applying our method to real many-view CTS or FIDA measurements, one could determine tomographies of 2D fast-ion velocity distribution functions experimentally.

AB - We compute tomographies of 2D fast-ion velocity distribution functions from synthetic collective Thomson scattering (CTS) and fast-ion D (FIDA) 1D measurements using a new reconstruction prescription. Contradicting conventional wisdom we demonstrate that one single 1D CTS or FIDA view suffices to compute accurate tomographies of arbitrary 2D functions under idealized conditions. Under simulated experimental conditions, single-view tomographies do not resemble the original fast-ion velocity distribution functions but nevertheless show their coarsest features. For CTS or FIDA systems with many simultaneous views on the same measurement volume, the resemblance improves with the number of available views, even if the resolution in each view is varied inversely proportional to the number of views, so that the total number of measurements in all views is the same. With a realistic four-view system, tomographies of a beam ion velocity distribution function at ASDEX Upgrade reproduce the general shape of the function and the location of the maxima at full and half injection energy of the beam ions. By applying our method to real many-view CTS or FIDA measurements, one could determine tomographies of 2D fast-ion velocity distribution functions experimentally.

KW - Instrumentation and measurement

KW - Plasma physics

U2 - 10.1088/0029-5515/52/10/103008

DO - 10.1088/0029-5515/52/10/103008

JO - Nuclear Fusion

JF - Nuclear Fusion

SN - 0029-5515

IS - 10

VL - 52

SP - 103008

ER -