27D42P
Study of Filament Features of Edge Plasma Fluctuations in Heliotron J臧臨閣1，大島慎介2，西野信博3，水内亨2，笠嶋慶純1，沙夢雨1，橋本 絋平1，向井清史4，李炫庸1，長崎百伸2，岡田浩之2，南貴司2，小林進二2，山本聡2，史楠2，
木島滋2，中村祐司1，佐野史道2
ZANG Linge1, S. OHSHIMA2, N. NISHINO3, T. MIZUUCHI2, K. KASAJIMA1, M. SHA1, K. HASHIMOTO1,
et al.

京大エネ科1, 京大エネ研2 , 広大院工3, 核融合研4
GSES Kyoto Univ.1, IAE Kyoto Univ.2, GSE Hiroshima Univ. 3, NIFS4
To investigate plasma fluctuations and particle
transport around LCFS region, a Langmuir probearray has been installed at #14.5 section inHeliotron J. In a condition-fixed ECH discharge
series, supersonic molecular-beam (SMB) wasinjected at 222ms from #11.5 port. The Langmuirprobe array was scanned along the radial direction
shot by shot to get the radial profiles of ion
saturation current (Is) and floating potential (Vf).
The conditional average (CA) method is applied
to Is (A means 2kHz high pass filtered signal of A)
data to extract the blob. The trigger condition of CA
is set to 2.5σ in this case, where σ is the standard
deviation of Is during a time window of 5ms . The
CA results of Is, Ep and a blob-induced particle
flux blob at two radial positions (r-a = -4 mm and+10 mm) are shown in Figs. 1(a) and (b). Here, Theblob is calculated by Is ∙ Ep , where Ep is thepoloidal electric field evaluated from two floating
potential signals of two electrodes arranged in thepoloidal direction. The positive blob means theoutward flux. The shapes of Is, Ep and blob just(a)HJ45445 r−a=10mm

225−230ms
245−250ms

0.04
0.02021(a)

0(b)

(c)
5225−230ms
245−250ms

−1

200.1
0.05
0−40

Er /(kV/m)

0.1
Is /AFlux(Is×Ep)/(A⋅kV/m)

Ep Fluctuation /(kV/m)

−0.02

0.05

−6−2−4−8−200dt/μs

2040−40−200dt/μs

2040Figure 1. Auto CA of Is, cross CA of Ep and blob induced
particle flux; red: 225-230ms, blue: 245-250ms. Location: (a)r-a=-4mm; (b) r-a=10mm.

0−10−10 0 10 20 30 40 50 −10 0 10 20 30 40 50
Radial Position(r−a)/mm

Partile Flux By Blob/A.U.

Is Fluctuation /A

0.06(b)

HJ45453 r−a=−4mm

after SMBI (225-230 ms, red lines in Fig.1) do notchange very much between r-a = -4 mm and +10mm, here the blob count number per millisecond isabout 3-4 for each position. On the other hand, longafter SMBI (245-250 ms, blue lines), Ep-structure
is different between two positions, r-a = -4mm and10mm. A characteristic structure, which is usuallyobserved for the blob, is not observed at r-a = -4mm, but, at r-a = +10 mm, the characteristic
structure is observed. This and the data in-between
the two position suggest the blobs are bornprobably near r-a = +10 mm in this timing (longafter SMBI). The averaged particle flux carried by asingle blob reduced to a small value compared tothat at 225-230 ms, due to smaller values of Is andEp. The count number per millisecond, however,increased from 1 to 6 at this timing.
Figure 2 shows the radial profiles of time
averaged Is, Er (radial electric field) and total blob
during the time window (calculated from the CAresults). In Fig. 2(a), the gradient of Is at245-250ms (long after SMBI) is much steeper thanthat at 225-230ms (just after SMBI). As in Fig. 2(c),however, the blob-induced particle flux at 245-250
ms is much reduced from that at 225-230 ms. The
much steeper Er profile in the region of -4 mm < r-a< +6 mm long after SMBI may be a candidate toexplain the reduced blob-induced particle flux andincreased count number. It can be expected that thesheared flow might tear up the coherent blob
structures and reduced the blob-induced transport.

432
10−10 0 10 20 30 40 50

Figure 2. Radial profiles of (a) Is; (b) Er; (c) particle flux
induced by blob. Red: 225-230ms, just after SMBI. Blue:245-250ms.