(MAP) Session Report
Date: April 11, 2024
Time: 14:20 - 16:45
Shot#: #189413 – #189459 (47 shots)
Prior wall conditioning: NO
Divertor pump: ONGas puff: H2, C pellet, TESPEL
IPD: ON
NBI#(1, 2, 3, 4, 5)=gas(H, H, H, H, H)=P(4.8, 4.3, 4.3, 3.7, 6.0)MW
ECH(77GHz)=ant(5.5-Uout (or 1.5U), 2-OUR)=P(698, 380)kW
ECH(154GHz)=ant(2-OLL, 2-OUL , 2-OLR)=P(705, 889, 982)kW
ECH(56GHz)=ant(1.5U)=P(-)kW
ICH(3.5U, 3.5L, 4.5U, 4.5L)=P(0.0, 0.0, 0.0, 0.0)MW

April. 12, 2024 (G. Motojima)

Topics
1. The evaluation of the toroidal uniformity of impurity deposition for effective real-time wall conditioning
using the IPD (M. Shoji)
2. Impurity transport study in the plasma with an impurity hole by means of TESPEL (D.M.
Roque(Ciemat), N. Tamura)

The evaluation of the toroidal uniformity of impurity deposition for effective
real-time wall conditioning using the Impurity Powder Dropper(M. Shoji)

Experimental conditions:(Rax, Polarity, Bt, γ, Bq) = (3.60 m, CW, 2.75 T, 1.2538, 100%), Shots: #189413 - #189434
ECH: only for start-up, NBI: 1-5, IPD: Lithium

Objective:
The toroidal uniformity of the impurity
deposition on divertor plates by impurity
powder injection is investigated using two
manipulators installed in different toroidal
positions (4.5-L and 10.5-L) for different
impurity powders (boron and lithium).

Experiment:

2.5-U#189421 10.5-U#189421
Target plate

Li ablation
Inboard

Inboard

Lithium powders (d=500 µm) were dropped from the impurity powder
dropper (IPD) in low-density plasma discharges (ne〜1.5×1019 m-3), in whichcarbon target plates were exposed to a lower divertor leg in two different
toroidal positions (4.5-L and 10.5-L) for Rax=3.60 m.

#189421

4.5-U
Target plate

Results:
The two target plates were successfully exposed to the divertor plasma for 16discharges. The deposited lithium density profile on the plates will becompared to that of boron and investigated by PSI simulation codes.

InboardTransport studies of TESPEL injected impurities in plasmas during impurity
hole (D. Medina Roque, N. Tamura, I. García Cortés, K. J. McCarthy et al.)Magnetic configuration: (Rax, Polarity, Bt, γ, Bq) = (3,55 m, CW, 2.789 T, 1.2538, 100.0%)
Shots: #189436 - #189459
Goal of this experimentl To characterize impurity transport in impurity hole hydrogen plasma conditions in LHD, we use 700um-shell type TESPELs containing
single tracers.
l Obtain data for comparisons with future results in W7-X and TJ-II.
Background & Motivationl The impurity hole phenomenon seems to be characterized by a +ve Er at the plasma edge and a -ve Er in the plasmacore à different convection velocities of impurities if neoclassical transport is relevant.
ü Estimate an impurity decay time from the line intensity evolution for injected elements (Ti, Cu, and Mo) for plasmas w/ and w/oimpurity hole using EUV/VUV spectrometer SOXMOS (its wavelength range from 19.7 to 34.1 nm with a 133.6 g/mm

grating for Ti, from 14.5 to 27.4 nm with a 133.6 g/mm for Cu, and from 8.9 to 13.2 nm with a 600 g/mm grating forMo).
l Comparison of experimental results obtained with and without impurity hole in NBI heated plasmas with a considered electron
density range of 1E19

Transport studies of TESPEL injected impurities in plasmas with and without
an impurity hole (D. Medina Roque, N. Tamura, I. García Cortés, K. J. McCarthy et al.)Resultsl 17 TESPELs are successfully injected at 4.825s (9 into w/ imp hole)and (8 into w/o imp hole) with carbon pellet at 4.6s and ne of 1e19 m-3
2 heating patterns are appliedA) w/o imp. hole, NB#1(5.8s-7.8s), NB#2,3(3.3s-5.3s), NB#4,5(4s-6s)B) w imp. hole, NB#1(5.8s-7.8s), NB#2,3(4s-6s), NB#4,5(3.3s-5.3s)
Typ waveformsA)

B)

l We obtained data for all impurities w/ and w/o imp.
hole plasmas.
l Preliminary analysis of Er and profiles evolution shows
no difference between w/ and w/o.
l Impurity confinement time from SOXMOS signals andEr from HIBP will be analyzed.