Neutral Beam Injectors
K. Nagaoka, K. Tsumori, K. Ikeda, H. Nakano, M. Kisaki, Y. Fujiwara, H. Nuga, M. Osakabe, T. Kondo,
M. Sato, M. Shibuya, H. Sekigushi, S. Komada, T. Kamiya,e-mail: nagaoka@nifs.ac.jp

1.

Objective
Neutral beam injection (NBI) is the most powerful tool for plasma heating on LHD [1]. The plasma
breakdown is also available due to NBI, which provides a variety of plasma operation such as a magnetic
configuration without electron cyclotron resonance [2].

2. Appratus
2.1. Configuration of NBIs
Three NBIs (NBI#1,#2,#3) inject the beam tangentially and produced mainly passing fast ions circulatingin the clockwise direction for NBI#2 and counter clockwise direction for NBI#1 and #3. Two NBIs (#4and #5) provide perpendicular beam injection to the magnetic field. The detailed port arrangement of NBI
is shown in Figure 1.

Fig. 1. Top view of LHD and arrangement of NBIs. .

2.2. Typical parameters of beam operation
Three negative-ion-based neutral beam injectors (NBI#1,#2,#3) [3] and two positive-ion-based beam
injectors (NBI#4,#5). Deuterium beam injection is operational from 19th experimental campaign of LHD.
However, hydrogen beams are also required for the initial phase and closing phase of this campaign. Inorder to produce good plasmas in a variety of conditions, negative-NBI will be kept the condition
optimized for hydrogen beam operation, while positive-NBI will be optimized for deuterium beamoperation. The typical port-through power is summarized in the Table 1.

# NBI

IS typePower for H

Energy for H

Power for D

Energy for D

NBI#1

negative6 MW190 keV

3 MW

180 keV

NBI#2

negative

5 MW

180 keV

3 MW

180 keV

NBI#3

negative

5 MW

180 keV

3 MW

180 keV

NBI#4

positive

6 MW

40 keV

9 MW

60 keV

NBI#5

positive

6 MW

40 keV

9 MW

80 keV

Table 1. Typical parameters of NBI injection in the case of shortpulse operation with duration of 1 - 2 sec.
3.

Beam injection pattern
The beam operation pattern is controlled by following parameters,-

Start time (3.0 -7.0 sec)

-Beam duration (0.5 - 2.0 sec)

-Power modulation duty (optional)

The waveform of NBI injection pattern can be produced by the LHD portal web server (http://kaisekidev3.lhd.nifs.ac.jp/rails/op_pattern/op_pattern). The beam modulation (ON/OFF) is available
for NBI#4 and #5. The minimum of beam off time is 20 msec and the maximum pulse number during
one discharge of LHD is 20. Please complete to input the beam operation pattern in the LHD portal
server until the day before the experiment, then the data is shared with the beam operators. The beam
modulation of NBI#1,#2 and #3 is optionally available. If you request such optional beam operation,please contact to NBI operation managers, K. Nagaoka (ext.2177) one week before the experiment.

4.

How to see NBI data

4.1.

summary sheet
The NBI waveform can be seen in the main monitor just after the plasma discharge. The PDF file ofsummary sheet is available from LHD portal server.

4.2

Kaiseki-data server
The time evolution of detailed beam operation such as the beam energy, beam power, on time ,,, can beobtained from Kaiski-data server. The list of data related to NBI operation is summarized in Table 2.

file_namenbpwr_tot_temporalnb1pwr

nb2pwrnb3pwr

nb1pwr_temporalnb2pwr_temporalexplanation of the data: all data is given as a function ofname_dataunit

Pport-through_t-nb-all

MW

Pport-through_r-nb-all

MW

Energy_NB1

keV

Energy of beam ions of NBI#1

Port-Through_NB1

MWPort-through power of NBI#1

Energy_NB2

keV

Energy of beam ions of NBI#2

Port-Through_NB2

MWPort-through power of NBI#2

Energy_NB3

keV

Energy of beam ions of NBI#3

Port-Through_NB3

MWPort-through power of NBI#3

Energy_NB4keV

Energy of beam ions of NBI#4

Port-Through_NB4

MW

Port-through power of NBI#4

Energy_NB5

keV

Energy of beam ions of NBI#5

Port-Through_NB5

MW

Port-through power of NBI#5

Ebeam_nb1

keV

Energy of beam ions of NBI#1

Pport-through_nb1

kW

Port-through power of NBI#1

Pdeposit_nb1

kW

Ebeam_nb2

keV

Energy of beam ions of NBI#2

Pport-through_nb2

kW

Port-through power of NBI#2

Pdeposit_nb2

kW

Ebeam_nb3

keV

Energy of beam ions of NBI#3

Pport-through_nb3

kW

Port-through power of NBI#3Pdeposit_nb3

kW

Ebeam_nb1

keV

Energy of beam ions of NBI#1

Pport-though[MW]MWPort-through power of NBI#1

time
Total port-through power of tangentally injected beam
(NBI#1,#2,#3)
Total port-through power of perpendicularly injected beam
(NBI#4,#5)

Deposited beam#1 power into plasma (Pportthrogh Psinethrough)Deposited beam#2 power into plasma (Pportthrogh Psinethrough)Deposited beam#2 power into plasma (Pportthrogh Psinethrough)Ion-statusA

0: no operation of ion source 1A, 1:beam acceleration

Ion-statusB

0: no operation of ion source 1B, 1:beam acceleration

Ebeam_nb2

keV

Energy of beam ions of NBI#2

Pport-through_nb2

MWPort-through power of NBI#2

Ion-stsA_nb2

0: no operation of ion source 2A, 1:beam acceleration

Ion-stsB_nb2

nb3pwr_temporalnb4apwr_temporal

nb4bpwr_temporalnb5apwr_temporal

nb5bpwr_temporal

0: no operation of ion source 2B, 1:beam acceleration

Ebeam_nb3

keV

Energy of beam ions of NBI#3

Pport-through_nb3

MWPort-through power of NBI#3

Ion-stsA_nb3

0: no operation of ion source 3A, 1:beam acceleration

Ion-stsB_nb30: no operation of ion source 3B, 1:beam acceleration

Ebeam_nb4akeV

Energy of beam ions of NBI#4a

Pport-through_nb4aMWPort-through power of NBI#4a

Ion-stsU_nb4a0: no operation of ion source 4UA, 1:beam acceleration

Ion-stsL_nb4a0: no operation of ion source 4LA, 1:beam acceleration

Ebeam_nb4bkeV

Energy of beam ions of NBI#4b

Pport-through_nb4bMW

Port-through power of NBI#4b

Ion-stsU_nb4b0: no operation of ion source 4UB, 1:beam acceleration

Ion-stsL_nb4b0: no operation of ion source 4LB, 1:beam acceleration

Ebeam_nb5akeV

Energy of beam ions of NBI#5a

Pport-through_nb5a

MWPort-through power of NBI#5a

Ion-stsU_nb5a0: no operation of ion source 5UA, 1:beam acceleration

Ion-stsL_nb5a0: no operation of ion source 5LA, 1:beam acceleration

Ebeam_nb5bkeV

Energy of beam ions of NBI#5b

Pport-through_nb5b

MW

Port-through power of NBI#5b

Ion-stsU_nb5b0: no operation of ion source 5UB, 1:beam acceleration

Ion-stsL_nb5b0: no operation of ion source 5LB, 1:beam acceleration

Table 2. List of NBI data available in Kaiseki-data server. The
temporal data is available just after the shot, however, nbi1,2,3_pwr
are a few days after the shot.
5.

Remarks
In general, negative-ion-based NBIs need commissioning to provide high power and stable beaminjection. Please attention the schedule of NBI operation, which is announced before every campaign ofLHD experiment. If you need CXS diagnostic for getting ion temperature profile, rotation profile,carbon density profile, etc., the beam modulation of NBI#4 and/or #5 is necessary. When you plan touse MSE diagnostic, please inform to NBI operation managers (K.T. and K.N.) before fix the experimentschedule, because optional beam operation is necessary to get current profile measurement.

References[1] Y. Takeiri, et al., Fusion Science and Technology 58 (2010) 482.
[2] O. Kaneko, et al., Fusion Science and Technology 58 (2010) 497.
[3] K. Tsumori, et al., Fusion Science and Technology 58 (2010) 489.