TJ-II:Heavy Ion Beam Probe: Difference between revisions

Jump to navigation Jump to search

TJ-II:Heavy Ion Beam Probe (view source)

Revision as of 08:05, 13 May 2023

1,045 bytes added ,  13 May 2023
m
→‎HIBP 2
No edit summary
 
(12 intermediate revisions by 2 users not shown)
Line 1: Line 1:
[[TJ-II]] disposes of Heavy Ion Beam Probe systems.
== HIBP 1 ==
[[File:TJ-II_HIBP_diagram.png|350px|thumb|right|HIBP probe diagram]]
[[File:TJ-II_HIBP_diagram.png|350px|thumb|right|HIBP probe diagram]]


At [[TJ-II]], the advanced Heavy Ion Beam Probe can simultaneously measure the plasma electric potential ''&phi;'', the electron density ''n<sub>e</sub>'', and a poloidal magnetic field component ''B<sub>p</sub>'' at a point inside the plasma.
The advanced Heavy Ion Beam Probe can simultaneously measure the plasma electric potential ''&phi;'', the electron density ''n<sub>e</sub>'', and a poloidal magnetic field component ''B<sub>p</sub>'' at a point inside the plasma.
<ref>[http://link.aip.org/link/?RSINAK/72/583/1 I.S. Bondarenko et al., ''Installation of an advanced heavy ion beam diagnostic on the TJ-II stellarator'', Rev. Sci. Instrum. '''72''', 583 (2001)]</ref>
<ref>I.S. Bondarenko et al., ''Installation of an advanced heavy ion beam diagnostic on the TJ-II stellarator'', [[doi:10.1063/1.1310593|Rev. Sci. Instrum. '''72''', 583 (2001)]]</ref>
<ref>[http://dx.doi.org/10.1016/S0920-3796(01)00428-8 L.I. Krupnik et al., ''The first operation of the advanced heavy ion beam probing diagnostic on the TJ-II flexible heliac'', Fusion Engineering and Design '''56-57''' (2001) 935]</ref>
<ref>L.I. Krupnik et al., ''The first operation of the advanced heavy ion beam probing diagnostic on the TJ-II flexible heliac'', [[doi:10.1016/S0920-3796(01)00428-8|Fusion Engineering and Design '''56-57''' (2001) 935]]</ref>
<ref>[http://link.aip.org/link/?RSINAK/75/1826/1 I.S. Bondarenko et al, ''High intensity alkali ion sources for plasma diagnostics'', Rev. Sci. Instrum. '''75''' (2004) 1826]</ref>
<ref>I.S. Bondarenko et al, ''High intensity alkali ion sources for plasma diagnostics'', [[doi:10.1063/1.1699512|Rev. Sci. Instrum. '''75''' (2004) 1826]]</ref>
<ref>[http://dx.doi.org/10.1007/s10582-005-0044-8 L. Krupnik et al, ''Radial electric fields and confinement in the TJ-II stellarator'', Czechoslovak Journal of Physics '''55''', 3 (2005) 317-339(23)]</ref>
<ref>L. Krupnik et al, ''Radial electric fields and confinement in the TJ-II stellarator'', [[doi:10.1007/s10582-005-0044-8|Czechoslovak Journal of Physics '''55''', 3 (2005) 317-339(23)]]</ref>
<ref>[http://dx.doi.org/10.1016/j.fusengdes.2006.04.029 L. Pereira et al, ''Control and data acquisition system for the multiple cell array detector of the TJ-II heavy ion beam diagnostic'', Fusion Engineering and Design '''81''', Issues 15-17 (2006) 1885-1889]</ref>
<ref>L. Pereira et al, ''Control and data acquisition system for the multiple cell array detector of the TJ-II heavy ion beam diagnostic'', [[doi:10.1016/j.fusengdes.2006.04.029|Fusion Engineering and Design '''81''', Issues 15-17 (2006) 1885-1889]]</ref>
<ref>[http://www.new.ans.org/pubs/journals/fst/a_1284 A.V. Melnikov et al, ''Plasma Potential Evolution Study by HIBP Diagnostic During NBI Experiments in the TJ-II Stellarator'', Fusion Science and Technology '''51''', 1 (2007) 31-37]</ref>
<ref>A.V. Melnikov et al, ''Plasma Potential Evolution Study by HIBP Diagnostic During NBI Experiments in the TJ-II Stellarator'', [http://www.new.ans.org/pubs/journals/fst/a_1284 Fusion Science and Technology '''51''', 1 (2007) 31-37]</ref>
<ref>A.V. Melnikov, L.I. Krupnik, C. Hidalgo, et al, ''Diagnostic advances in Heavy Ion Beam Probing in the T-10 tokamak and TJ-II stellarator'', [http://ocs.ciemat.es/EPS2013PAP/pdf/O6.505.pdf 40<sup>th</sup> EPS Conference (2013) O6.505]</ref>
This point can be scanned through the plasma cross-section by varying the deflection potentials (active beam control).
This point can be scanned through the plasma cross-section by varying the deflection potentials (active beam control).
A multiple cell array detector (MCAD) has been developed to investigate the spatial structure of plasma turbulence.
A multiple cell array detector (MCAD) has been developed to investigate the spatial structure of plasma turbulence.
<ref>[http://link.aip.org/link/?RSINAK/75/3511/1 B. Gonçalves et al, ''Operation of a multiple cell array detector in plasma experiments with a heavy ion beam diagnostic'', Rev. Sci. Instrum. '''75''' (2004) 3511]</ref>
<ref>B. Gonçalves et al, ''Operation of a multiple cell array detector in plasma experiments with a heavy ion beam diagnostic'', [[doi:10.1063/1.1785276|Rev. Sci. Instrum. '''75''' (2004) 3511]]</ref>
The system is located in [[TJ-II:Sectors|sector]] B4.
The system is located in [[TJ-II:Sectors|sector]] B4.
[[File:TJ-II_HIBP.png|350px|thumb|left|HIBP probe composite photo (taken around 2002)]]
[[File:TJ-II_HIBP.png|350px|thumb|right|HIBP probe composite photo (taken around 2002)]]
 
== HIBP 2 ==
 
A second, similar system has been installed in [[TJ-II:Sectors|sector]] A4 (see photo) <ref>A.V. Melnikov et al., ''Control and data acquisition for dual HIBP diagnostics in the TJ-II stellarator'', [[doi:10.1016/j.fusengdes.2015.01.015|Fusion Eng. Des. '''96-97''' (2015) 724-728]]</ref>.
The purpose of this second system is to study plasma potential asymmetries and long range correlations of turbulence.<ref>A.V. Melnikov et al., ''Heavy ion beam probing—diagnostics to study potential and turbulence in toroidal plasmas'', [[doi:10.1088/1741-4326/aa5382|Nucl. Fusion '''57''' (2017) 072004]]</ref>
[[File:IMG 1627.JPG|350px|thumb|right|Installation of the second HIBP probe (March, 2011)]]


== Operation principle ==
== Operation principle ==
Line 18: Line 29:
The Heavy Ion Beam Probe (HIBP) is a unique diagnostic for its ability to measure plasma electric potential well inside the plasma column, where no material probes can be inserted. The operating principle is as follows: heavy ions <math>I^q</math> with charge <math>q</math> (Cs<math>^+</math> in the case of TJ-II) are accelerated to high energies (several hundred keV) and injected as a continuous jet into the plasma column. The interaction with the plasma yields a fan of secondary ions <math>I^{q'}</math> that are more strongly deflected by the magnetic field. Those secondary ions produced in the so-called `sample volume' are collected in an energy analyser. Their energy contains information on the electric potential in the sample volume. Trajectory reconstruction codes allow us to measure the position and reltive potential of the sample volume.
The Heavy Ion Beam Probe (HIBP) is a unique diagnostic for its ability to measure plasma electric potential well inside the plasma column, where no material probes can be inserted. The operating principle is as follows: heavy ions <math>I^q</math> with charge <math>q</math> (Cs<math>^+</math> in the case of TJ-II) are accelerated to high energies (several hundred keV) and injected as a continuous jet into the plasma column. The interaction with the plasma yields a fan of secondary ions <math>I^{q'}</math> that are more strongly deflected by the magnetic field. Those secondary ions produced in the so-called `sample volume' are collected in an energy analyser. Their energy contains information on the electric potential in the sample volume. Trajectory reconstruction codes allow us to measure the position and reltive potential of the sample volume.


===Formal expression of the electric potential <math>\phi</math>===
===Formal expression of the electric potential ''&phi;'' ===
 
Refering to the figure, we will denote as <math>A</math>, <math>B</math> and <math>C</math> the injection, ionization and detection points respectively. The Hamiltonian of a charge in an electromagnetic field is
We'll denote as <math>A</math>, <math>B</math> and <math>C</math> the injection, ionization and detection points respectively. The Hamiltonian of a charge in an electromagnetic field is
[[Image:HIBP3.png|256px|thumb|right|alt=Schematic HIBP operation principle.|Schematic HIBP operation principle.]]


:<math>
:<math>
Line 86: Line 97:
</math>
</math>


===Operational expression for the electric potential <math>\phi</math>===
===Operational expression for the electric potential ''&phi;'' ===


The energy analyser of the HIBP diagnostic at TJ-II is of the Proca-Green type. The kinetic energy of the secondary ions entering the analyser is given by
The energy analyser of the HIBP diagnostic at TJ-II is of the Proca-Green type. The kinetic energy of the secondary ions entering the analyser is given by
Retrieved from "http://wiki.fusenet.eu/wiki/Special:MobileDiff/2653...7582"

Navigation menu