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An international journal of news from the stellarator community
Editor: James A. Rome Issue 178 April 2022
E-Mail: James.Rome@ Phone: +1 (865) 482-5643
On the Web at
23rd LHD experimental
campaign successfully completed
The 23rd experimental campaign of the Large Helical
Device (LHD) in Toki, Japan, was successfully completed
in February 2022. During the 17 weeks of the campaign,
LHD operated for 61 days, and 9257 discharges were
accomplished. Starting with this campaign, the main goal
of the experiments was changed from achieving worldleading
performance, such as highest temperature and longest
discharge duration, to acquiring scientific knowledge
that will deepen our understanding of magnetically confined
toroidal plasmas. In line with this change, the application
of heating devices such as electron cyclotron
heating (ECH), ion cyclotron heating (ICH), and neutral
beam injection (NBI) heating was also changed from operations
aiming at highest performance to operations aiming
for stable, high-performance operation. As a result, no
major trouble with heating devices has occurred. The
change in the operation policy led to a higher plasma
experiment execution rate (98.6%) than the previous year
(96.7%). In addition, most of the 192 experiment idea proposals
submitted to the 23rd LHD experiment campaign
have been implemented, especially those from overseas
institutions. However, unfortunately, the impact of the
spread of COVID-19 has not subsided. Therefore, this
year, we continued to conduct remote experiments utilizing
Zoom and Microsoft Teams applications.
Some of the international collaborations at NIFS/LHD
have achieved excellent scientific accomplishments. For
example, F. Nespoli (PPPL) published a paper describing
the turbulence reduction during the boron powder injection
in LHD in Nature Physics (the article can be downloaded
here). And F. Warmer (IPP-Greifswald) has
published a paper describing the impact of magnetic configurations
on heat transport in stellarators and heliotrons
at Physical Review Letters (the article can be downloaded
here). In addition, to promote the results of international
collaborations at NIFS, NIFS has published a press release
on these impressive scientific results (see NIFS press
release in Nature Physics and Physical Review Letters for
Currently, NIFS strongly promotes open science in the
fusion community. Therefore, any researcher can access
LHD experimental data through the LHD Experiment
Data Repository. This means that any researcher can now
publish articles using LHD experimental data much more
easily than before. In addition, other repositories (Publications/
Scientific Achievements) make it easy to find out
what research papers have been published.
Next year will be the last year for experiments at LHD in
which deuterium can be used. Although it is unfortunate
that interactive experiments with deuterium cannot be performed
in the large stellarator/heliotron type experiment
devices (LHD and Wendelstein 7-X), we hope that the
fusion/plasma community will make good use of this last
opportunity at LHD. The schedule for next yearʼs LHD
experimental campaign will be similar to last yearʼs, but it
may start a little earlier than in the past. As in the previous
year, experimental proposals will be collected through the
website in June 2022. We look forward to receiving your
interesting and meaningful proposals for this campaign.
In this issue . . .
23rd LHD experimental campaign successfully
During the 17 weeks of the campaign, the Large Helical
Device (LHD) operated for 61 days, and 9257 discharges
were accomplished. Important papers are
cited, and proposals for experiments in the next campaign
can be submitted through the website in June.
The next campaign will be the last one to employ deuterium
in LHD. Any researcher can access LHD experimental
data through the LHD Experiment Data
Repository................................................................ 1
Stellarator News -2- April 2022
Katsumi Ida
(Executive Director on Science, Large Helical Device
Naoki Tamura
(Leader of the Mutiion Plasma Topical Group)
for the LHD Experiment Group
National Institute for Fusion Science, Japan

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