PMID- 31472602
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20190906
IS  - 1089-7623 (Electronic)
IS  - 0034-6748 (Linking)
VI  - 90
IP  - 8
DP  - 2019 Aug
TI  - The digital mirror Langmuir probe: Field programmable gate array implementation 
      of real-time Langmuir probe biasing.
PG  - 083504
LID - 10.1063/1.5109834 [doi]
AB  - High bandwidth, high spatial resolution measurements of electron temperature, 
      density, and plasma potential are valuable for resolving turbulence in the 
      boundary plasma of tokamaks. While conventional Langmuir probes can provide such 
      measurements, either their temporal or spatial resolution is limited: the former 
      by the sweep rate necessary for obtaining I-V characteristics and the latter by 
      the need to use multiple electrodes, as is the case in triple and double probe 
      configurations. The Mirror Langmuir Probe (MLP) bias technique overcomes these 
      limitations by rapidly switching the voltage on a single electrode cycling 
      between three bias states, each dynamically optimized for the local plasma 
      conditions. The MLP system on Alcator C-Mod used analog circuitry to perform this 
      function, measuring T(e), V(F), and I(sat) at 1.1 MSPS. Recently, a new prototype 
      digital MLP controller has been implemented on a Red Pitaya Field Programmable 
      Gate Array (FPGA) board which reproduces the functionality of the original 
      controller and performs all data acquisition. There is also the potential to 
      provide the plasma parameters externally for use with feedback control systems. 
      The use of FPGA technology means the system is readily customizable at a fraction 
      of the development time and implementation cost. A second Red Pitaya was used to 
      test the MLP by simulating the current response of a physical probe using C-Mod 
      experimental measurements. This project is available as a git repository to 
      facilitate extensibility (e.g., real-time control outputs and more voltage 
      states) and scalability through collaboration.
FAU - Vincent, C
AU  - Vincent C
AUID- ORCID: 000000027227409X
AD  - Department of Physics, Durham University, South Road, Durham, DH1 3LE, United 
      Kingdom.
FAU - McCarthy, W
AU  - McCarthy W
AUID- ORCID: 0000000180501128
AD  - Plasma Science and Fusion Centre, Massachusetts Institute of Technology, 77 
      Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
FAU - Golfinopoulos, T
AU  - Golfinopoulos T
AD  - Plasma Science and Fusion Centre, Massachusetts Institute of Technology, 77 
      Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
FAU - LaBombard, B
AU  - LaBombard B
AUID- ORCID: 0000000278419261
AD  - Plasma Science and Fusion Centre, Massachusetts Institute of Technology, 77 
      Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
FAU - Sharples, R
AU  - Sharples R
AUID- ORCID: 0000000334498583
AD  - Department of Physics, Durham University, South Road, Durham, DH1 3LE, United 
      Kingdom.
FAU - Lovell, J
AU  - Lovell J
AUID- ORCID: 0000000195653466
AD  - Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
FAU - Naylor, G
AU  - Naylor G
AD  - United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham 
      Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom.
FAU - Hall, S
AU  - Hall S
AD  - United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham 
      Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom.
FAU - Harrison, J
AU  - Harrison J
AD  - United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham 
      Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom.
FAU - Kuang, A Q
AU  - Kuang AQ
AUID- ORCID: 0000000289172911
AD  - Plasma Science and Fusion Centre, Massachusetts Institute of Technology, 77 
      Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Rev Sci Instrum
JT  - The Review of scientific instruments
JID - 0405571
SB  - IM
EDAT- 2019/09/02 06:00
MHDA- 2019/09/02 06:01
CRDT- 2019/09/02 06:00
PHST- 2019/09/02 06:00 [entrez]
PHST- 2019/09/02 06:00 [pubmed]
PHST- 2019/09/02 06:01 [medline]
AID - 10.1063/1.5109834 [doi]
PST - ppublish
SO  - Rev Sci Instrum. 2019 Aug;90(8):083504. doi: 10.1063/1.5109834.