Diagnostics: Difference between revisions

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[[File:Solar flare.png|420px|thumb|right|A prominence on the sun, an arc of plasma rising into the corona. Image credit: [http://sdo.gsfc.nasa.gov/ Solar Dynamics Observatory] (April, 2010)]]
Diagnostics are the eyes and ears of fusion reactors. They return vital parameters such as the temperature, the density, the impurity content, the magnetic field et cetera.  
Diagnostics are the eyes and ears of fusion reactors. They return vital parameters such as the temperature, the density, the impurity content, the magnetic field et cetera.  
A distinction can be made between ''active'' and ''passive'' diagnostics (the former requiring the injection of light beams, particles, or probes, while the latter is based on the observation of radiation and particles emitted spontaneously by the plasma).
A distinction can be made between ''active'' diagnostics (requiring the injection of light beams, particles, or probes and the observation of an induced effect), and ''passive'' diagnostics (based on the observation of radiation and particles emitted spontaneously by the plasma).
Below follows a list of different diagnostics, together with their main measurement parameters.
Below follows a list of different diagnostics, together with their main measurement parameters.


== Passive diagnostics ==


{| class="wikitable"  align="center" border="1"
{| class="wikitable"  align="center" border="1"
!''Name'' !!''Abbreviation''!!''Measurement parameters''
!''Name'' !!''Abbreviation''!!''Measurement parameters''
|-
|-
|Thomson Scattering || TS || Electron temperature <math>T_e</math>, electron density <math>n_e</math>
|Mirnov coils, pickup coils || - || Magnetic field components and fluctuations (outside plasma)
|-
|-
|Charge Exchange Recombination Spectroscopy || CXRS, CXS, CHERS, CER || Ion temperature <math>T_i</math>, toroidal and poloidal plasma rotation velocity <math>v_\phi</math>, <math>v_\theta</math>, impurity density <math>n_Z</math>
|Flux loops || - || Magnetic field (outside plasma)
|-
|Electron Cyclotron Emission || ECE, ECEi || Electron temperature <math>T_e</math>, electron temperature fluctuations (turbulence) <math>\tilde{T}_e</math> (local)
|-
|Soft X-Ray Emission || SXR || A combination of electron temperature <math>T_e</math>, electron density <math>n_e</math>, and effective charge <math>Z_{eff}</math> (line integral)
|-
|Bolometry || - || Broad spectrum emission (line integral)
|-
|H<sub>&alpha;</sub> monitors|| - || Emission of specific H<sub>&alpha;</sub> radiation
|-
|-
|Motional Stark Effect || MSE || Magnetic pitch angle <math>\tan(\gamma) = B_\theta/B_\phi</math>
|Spectroscopy || - || Monitoring of [[impurities]], etc. (line integral)
|}
 
== Active diagnostics ==
 
{| class="wikitable"  align="center" border="1"
!''Name'' !!''Abbreviation''!!''Measurement parameters''
|-
|-
|Electron Cyclotron Emission || ECE, ECEi || Electron temperature <math>T_e</math>, electron temperature fluctuations (turbulence) <math>\tilde{T}_e</math>
|Thomson Scattering || TS || Electron temperature <math>T_e</math>, electron density <math>n_e</math> (local)
|-
|-
|Soft X-Ray Emission || SXR || A combination of electron temperature <math>T_e</math>, electron density <math>n_e</math>, and effective charge <math>Z_{eff}</math>
|Charge Exchange Recombination Spectroscopy || CXRS, CXS, CHERS, CER || Ion temperature <math>T_i</math>, toroidal and poloidal plasma rotation velocity <math>v_\phi</math>, <math>v_\theta</math>, impurity density <math>n_Z</math>
|-
|-
|Mirnov coils, pickup coils || - || magnetic field components and fluctuations (outside plasma)
|Motional Stark Effect || MSE || Magnetic pitch angle <math>\tan(\gamma) = B_\theta/B_\phi</math>
|-
|-
|Heavy Ion Beam Probe || HIBP || Electron density <math>n_e</math>, plasma potential <math>\phi</math> <br>See [[TJ-II:Heavy Ion Beam Probe]]
|Heavy Ion Beam Probe || HIBP || Electron density <math>n_e</math>, plasma potential <math>\phi</math> (local) <br>See [[TJ-II:Heavy Ion Beam Probe]]
|-
|-
|Interferometry || - || Electron density <math>n_e</math> (line integral)
|Interferometry || - || Electron density <math>n_e</math> (line integral)
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|Polarimetry || - || Magnetic field pitch (line integral)
|Polarimetry || - || Magnetic field pitch (line integral)
|-
|-
|Reflectometry || - || Electron density <math>n_e</math> (edge profile, fluctuations)
|Reflectometry || - || Electron density <math>n_e</math> (local, fluctuations)
|-
|Langmuir probes || - || Ion saturation current, plasma potential, Mach number, etc. (local, fluctuations)
|-
|Diagnostic beams || - || Injection of Helium, Lithium, etc., and observation of emitted radiation (local, fluctuations)
|}
|}


A special bi-annual conference on fusion diagnostics is held in the U.S.: The [[Topical Conference on High Temperature Plasma Diagnostics]] (HTPD)
A special bi-annual conference on fusion diagnostics is held in the U.S.: The [[Topical Conference on High Temperature Plasma Diagnostics]] (HTPD)


== References ==
== References ==
* I.H. Hutchinson, ''Principles of Plasma Diagnostics'', Cambridge University Press; 2<sup>nd</sup> edition (2002) ISBN 978-0521803892
* I.H. Hutchinson, ''Principles of Plasma Diagnostics'', Cambridge University Press; 2<sup>nd</sup> edition (2002) {{ISBN|978-0521803892}}