BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:"Measuring the inboard side scrape-off layer of DIII-D plasmas usi
 ng Swing-Probes\, Accounting for Sheath Expansion in Langmuir Probe Analys
 es without a 4th Parameter\, and the DIII-D Inner-Wall-Limiter Heat Flux E
 xperiment"
DTSTART:20141110T103000
DTEND:20141110T113000
DTSTAMP:20260916T055401Z
UID:57ae553031d1e375da32e50ff0272d6f1783842347fc22f96f569280
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Cedric Tsui - EPFL-CRPP\, visiting from UCSD\, San Diego\,
  USA\nThis seminar serves as a general introduction for my work and myself
  to the CRPP. I will be focusing on topics that members of the CRPP should
  find interesting.\nTo measure the inboard side SOL of DIII-D plasmas\, a 
 pair of in-vessel swinging Langmuir probes were installed on the DIII-D ce
 nterpost. These probes make active measurements in a region that previousl
 y had nearly no diagnostic access\, making it impossible to fully constrai
 n plasma solutions. Designing these probes for this harsh environment pres
 ented a real challenge to DIII-D engineers.\nLangmuir probe analyses relie
 s upon a fitting of a theoretical I(V) function to thousands of sets of da
 ta for each probe and each shot.  The automatic fitting routine therefore
  needs to be highly reliable. This can be difficult in conditions where pl
 asma fluctuations introduce noise and where sheath-expansion effects are n
 on-negligible.  Sheath expansion can be accommodated for using an additio
 nal freely fitted parameter\, but this method is strongly influenced when 
 the data is noisy. We will demonstrate some of the drawbacks of this metho
 d and present a simple way to account for sheath expansion using the Child
 -Langmuir Law. This new method improves the reliability of the automatic f
 itting routine\, and is simple enough to be applied to a wide range of pro
 bes and plasma conditions.\nIn an inner-wall limiter experiment in DIII-D 
 requested by ITER\, the Swing-Probes made the first Langmuir probe measure
 ments of a narrow region of enhanced heat flux just outside the LCFS. Curr
 ently\, these are the only published data that show the narrow feature tha
 t is not taken with an IR Camera. Good agreement is shown between the Swin
 g-Probe and IR camera\, confirming that the narrow feature is not just an 
 artefact of the IR camera analyses.
LOCATION:PPB 019
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR