JPH0544995B2 - - Google Patents
Info
- Publication number
- JPH0544995B2 JPH0544995B2 JP59205544A JP20554484A JPH0544995B2 JP H0544995 B2 JPH0544995 B2 JP H0544995B2 JP 59205544 A JP59205544 A JP 59205544A JP 20554484 A JP20554484 A JP 20554484A JP H0544995 B2 JPH0544995 B2 JP H0544995B2
- Authority
- JP
- Japan
- Prior art keywords
- antenna
- faraday shield
- pipe
- pipes
- plasma
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/10—Nuclear fusion reactors
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- Plasma Technology (AREA)
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は、核融合装置のプラズマを追加熱する
高周波加熱装置に係り、特に、イオンサイクロト
ロン周波数帯高周波加熱装置のフアラデーシール
ドに関するものである。[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a high-frequency heating device for additionally heating the plasma of a nuclear fusion device, and particularly relates to a Faraday shield for a high-frequency heating device in the ion cyclotron frequency band. .
核融合装置のプラズマの加熱には、プラズマ中
に電流を通して加熱するジユール加熱があり、追
加熱としては、中性粒子入射加熱、高周波加熱等
がある。
For heating the plasma of a nuclear fusion device, there is Joule heating, which heats the plasma by passing an electric current through it, and additional heat includes neutral particle injection heating, high frequency heating, and the like.
高周波加熱法は、高周波電磁エネルギーをプラ
ズマに吸収させてプラズマの温度を上げる方法
で、使用する周波数によつて各種の方式があり、
その１つにイオンサイクロトロン周波数帯（以下
ICRFと略称する）高周波加熱がある。 The high-frequency heating method is a method of increasing the temperature of the plasma by absorbing high-frequency electromagnetic energy into the plasma, and there are various methods depending on the frequency used.
One of them is the ion cyclotron frequency band (hereinafter referred to as
There is radio frequency heating (abbreviated as ICRF).
ICRF高周波加熱装置は、第４図に示すように
高出力の百ＭHz帯の高周波を発生する高周波発振
器１、この高周波発振器１から発生した高周波出
力を伝送する同軸管３、この同軸管３に接続さ
れ、高周波出力をプラズマ４に放出するアンテナ
に相当する結合系５から構成されている。 As shown in Figure 4, the ICRF high-frequency heating device consists of a high-frequency oscillator 1 that generates high-output high-frequency waves in the 100 MHz band, a coaxial tube 3 that transmits the high-frequency output generated from the high-frequency oscillator 1, and a coaxial tube 3 that is connected to the coaxial tube 3. The coupling system 5 corresponds to an antenna that emits high frequency output to the plasma 4.
上記結合系５には、トカマク装置本体２との整
合性の面からＴ型リツジ導波管方式や、ループア
ンテナ方式があるが、ここではループアンテナ方
式を対象とする。 The coupling system 5 includes a T-shaped rigid waveguide system and a loop antenna system in terms of compatibility with the tokamak device main body 2, but the loop antenna system is targeted here.
このループアンテナ方式の結合系５は、同軸管
３の外周に設けられたフランジ６がトカマク装置
本体２に直接接続される。第５図に示すように同
軸管３の先端にはアンテナ導体７が取付けられ、
さらにアンテナ導体７のプラズマ４側にフアラデ
ーシールド８が装着されている。フアラデーシー
ルド８は、アンテナ導体７を流れる高周波電流の
つくる磁場はプラズマ側に通すが、静電的にはア
ンテナ導体７をシールドする。トカマク装置本体
２は高真空であるため、同軸管３の外導体３ａと
内導体３ｂ間は、フイードスルー９で真空シール
される。 In this loop antenna type coupling system 5, a flange 6 provided on the outer periphery of the coaxial tube 3 is directly connected to the tokamak device main body 2. As shown in FIG. 5, an antenna conductor 7 is attached to the tip of the coaxial tube 3.
Further, a Faraday shield 8 is attached to the plasma 4 side of the antenna conductor 7. The Faraday shield 8 allows the magnetic field created by the high frequency current flowing through the antenna conductor 7 to pass through to the plasma side, but electrostatically shields the antenna conductor 7. Since the tokamak device main body 2 is in a high vacuum, the space between the outer conductor 3a and the inner conductor 3b of the coaxial tube 3 is vacuum-sealed by the feedthrough 9.
フアラデーシールド８には、アンテナ導体を流
れる高周波によつて誘導電流が流れ、高周波損失
による発熱を生ずる。この他、フアラデーシール
ド８の熱負荷として、プラズマ４からの照射熱が
加わる。核融合の研究が進むにつれて、プラズマ
４が高温・高密度になると共に、高周波加熱装置
も大容量・長時間運転になり、フアラデーシール
ド８への熱負荷も約100W／cm2−約10秒と極めて
大きくなつてきている。従つて、フアラデーシー
ルドの構成も変化しており、従来の無垢の金属材
から、第６図に示すように、アンテナケーシング
１０の側面にジヤケツト１１を設け、このジヤケ
ツト１１とパイプ１２で構成するフアラデーシー
ルド８を接続して、冷却媒体をパイプ１２内に流
して冷却するようになつている。 An induced current flows through the Faraday shield 8 due to the high frequency waves flowing through the antenna conductor, causing heat generation due to high frequency loss. In addition, irradiation heat from the plasma 4 is added as a heat load on the Faraday shield 8. As nuclear fusion research progresses, the plasma 4 becomes hotter and denser, and the high-frequency heating equipment also becomes larger in capacity and operates for longer periods of time, increasing the heat load on the Faraday shield 8 to about 100 W/cm 2 - about 10 It is becoming extremely large with each passing second. Therefore, the structure of the Faraday shield has also changed, and instead of the conventional solid metal material, a jacket 11 is provided on the side of the antenna casing 10, and the shield is made up of this jacket 11 and a pipe 12, as shown in FIG. A faraday shield 8 is connected to the pipe 12, and a cooling medium is allowed to flow into the pipe 12 for cooling.
ところで、フアラデーシールドの高周波損失
は、第６図に示すようなアンテナの前面部１３ａ
とアンテナの前面部以外１３ｂでは発熱の性質が
異なる。即ち、アンテナ前面部１３ａでは、パイ
プ１２の周囲方向で、アンテナを通る電流に依つ
て決まるほぼ均一の発熱となる。一方、アンテナ
の前面部以外１３ｂでは、発熱はパイプ間の空隙
の大きさに依存し、第７図のようにパイプ１２の
ピツチをＵ、パイプ間の空隙をｇとすると、発熱
Ｑは
Ｑ∝（１／ｇ／Ｕ）2
となる。 By the way, the high frequency loss of the Faraday shield is caused by the front part 13a of the antenna as shown in FIG.
The characteristics of heat generation are different in the antenna other than the front part 13b. That is, in the antenna front section 13a, heat is generated almost uniformly in the circumferential direction of the pipe 12, which is determined by the current passing through the antenna. On the other hand, in areas other than the front part 13b of the antenna, the heat generation depends on the size of the gap between the pipes. As shown in Fig. 7, if the pitch of the pipe 12 is U and the gap between the pipes is g, the heat generation Q is Q∝ (1/g/U) 2 .
一般に、フアラデーシールドのパイプの断面形
状が一様な場合アンテナの前面部に比べてアンテ
ナ前面以外の発熱が大きい。高周波加熱装置の大
容量化、出力の長時間化に伴つて、高周波損失に
よるフアラデーシールドの温度上昇は数百度にも
達することがあり、熱膨脹によつて過大な熱応力
を生じ、機器の信頼性が低下する。 Generally, when the pipe of the Faraday shield has a uniform cross-sectional shape, heat generation is greater in areas other than the front of the antenna than in the front of the antenna. As high-frequency heating equipment becomes larger in capacity and output over longer periods of time, the temperature rise of the Faraday shield due to high-frequency loss can reach several hundred degrees, causing excessive thermal stress due to thermal expansion and damaging equipment. Reliability decreases.
また、特にアンテナ前面以外の高周波損失を低
減するために、パイプ間の空隙を一様に大きくす
ることは、プラズマ粒子のアンテナへの衝突が増
え、アンテナ表面の損傷が増加すると共に、衝突
による２次電子によつてアンテナの絶縁破壊を生
ずる可能性がある。 In addition, uniformly increasing the air gap between the pipes in order to reduce high-frequency loss in areas other than the front of the antenna will increase the number of plasma particles colliding with the antenna, increasing damage to the antenna surface, and increasing the number of plasma particles caused by collisions. The secondary electrons may cause dielectric breakdown of the antenna.
本発明の目的は、フアラデーシールドに発生す
る高周波損失を低減して温度上昇を抑え、かつア
ンテナの電圧を低下させることによつてアンテナ
の絶縁破壊の可能性を小さくして機器の信頼性を
高めることにある。
The purpose of the present invention is to reduce the high frequency loss generated in the Faraday shield to suppress temperature rise, and to reduce the possibility of dielectric breakdown of the antenna by lowering the voltage of the antenna, thereby improving the reliability of equipment. The aim is to increase
本発明によるフアラデーシールドは、アンテナ
の前面部においては、パイプ相互間の空間が狭く
なる様にアンテナに向きあう面の広い断面形状と
し、アンテナの前面部以外の部分は、パイプ相互
間の空間が広くなるようにアンテナに向きあう面
の狭い断面形状とすることにより、フアラデーシ
ールドの高周波損失を低減して、温度上昇による
熱応力を緩和し、かつ、アンテナの絶縁破壊の可
能性を小さくする。
The Faraday shield according to the present invention has a wide cross-sectional shape on the surface facing the antenna so that the space between the pipes is narrow in the front part of the antenna, and the part other than the front part of the antenna has a wide cross-sectional shape between the pipes By creating a narrow cross-sectional shape on the surface facing the antenna so that the space is wider, the high frequency loss of the Faraday shield is reduced, alleviating thermal stress caused by temperature rise, and the possibility of dielectric breakdown of the antenna. Make smaller.
（実施例の構成）
本発明の一実施例のフアラデーシールドを第１
図と第２図に示す。第１図はアンテナ７の前面部
のフアラデーシールドのパイプ１２の断面形状
で、パイプ１２の間の空間が狭くなるように縦長
の断面を用いる。また、第２図は、アンテナ７の
前面以外のフアラデーシールドのパイプ１２の断
面形状で、パイプ間の空間を広くする様横長の断
面である。従つて、フアラデーシールドのパイプ
１２は、一本のパイプで、長手方向に断面形状の
異なつたものとなる。パイプ１２の内側は、第１
図・第２図に示すように穴が空いており、冷却媒
体を流すことができる。パイプ１２の両端は、第
６図に示すように、冷却媒体のヘツダを兼ねたア
ンテナケーシング１０に溶接される。
(Configuration of Example) The Faraday shield of one example of the present invention is
As shown in Fig. and Fig. 2. FIG. 1 shows the cross-sectional shape of the pipes 12 of the Faraday shield at the front of the antenna 7, and a vertically long cross-section is used so that the space between the pipes 12 is narrow. Further, FIG. 2 shows the cross-sectional shape of the pipe 12 of the Faraday shield other than the front surface of the antenna 7, and the cross-section is horizontally long so as to widen the space between the pipes. Therefore, the pipe 12 of the Faraday shield is a single pipe with different cross-sectional shapes in the longitudinal direction. The inside of the pipe 12 has a first
As shown in Figure 2, there are holes through which cooling medium can flow. Both ends of the pipe 12 are welded to the antenna casing 10, which also serves as a header for the cooling medium, as shown in FIG.
（実施例の作用）
まず、アンテナ前面部のフアラデーシールド８
について、パイプ１２間の空間を小さくすること
は、アンテナ７とシールド８との相対する面積が
増えるため、この部分の静電容量ｃが増加する。
フアラデーシールド８のパイプ１２は外導体と接
続されているから、静電容量の増加によつてアン
テナ部の電圧ｖは、ｖ∝１／ｃにより減少する。従
つて、アンテナ７とフアラデーシールド８、ある
いはケーシング１０との絶縁破壊の可能性が低下
する。(Function of the embodiment) First, Faraday shield 8 on the front part of the antenna.
Regarding this, reducing the space between the pipes 12 increases the area where the antenna 7 and the shield 8 face each other, so the capacitance c of this portion increases.
Since the pipe 12 of the Faraday shield 8 is connected to the outer conductor, the voltage v at the antenna section decreases by v∝1/c due to an increase in capacitance. Therefore, the possibility of dielectric breakdown between the antenna 7 and the Faraday shield 8 or the casing 10 is reduced.
また、アンテナの電流Ｉは、アンテナの中心か
ら通電の方向の距離をｙ、波長をλとすると、
Ｉ＝I0cos2π／λｙ
の分布をしている。従つて、高周波損失はcos2
2π／λｙに比例する。いま、アンテナ７とフアラデ
ーシールド８の静電容量が増加すると、系全体の
静電容量ｃも増加する。波長λは√∝Ｐ１／λの
関係があるから、ｃの増加によつてλが減少す
る。高周波損失は、cos22π／λｙに比例しているか
ら、ｙの増加に伴つて減少するが、λの低下によ
りその減少の割合は大きくなる。 Furthermore, the antenna current I has a distribution of I=I 0 cos2π/λy, where y is the distance from the center of the antenna in the current direction and λ is the wavelength. Therefore, the high frequency loss is cos 2
Proportional to 2π/λy. Now, when the capacitance of the antenna 7 and Faraday shield 8 increases, the capacitance c of the entire system also increases. Since the wavelength λ has a relationship of √∝P1/λ, λ decreases as c increases. Since the high frequency loss is proportional to cos 2 2π/λy, it decreases as y increases, but the rate of decrease increases as λ decreases.
さらに、アンテナの前面以外の部分では、前に
も述べたように、フアラデーシールドの高周波損
失Ｑと、パイプ１２間の空〓の大きさｇはＱ∝
（１／ｇ）2であるから、第２図に示すように、パイプ
１２の断面を横長にすることによつてｇが増加
し、高周波損失Ｑが減少する。 Furthermore, in areas other than the front of the antenna, as mentioned earlier, the high frequency loss Q of the Faraday shield and the size g of the air space between the pipes 12 are Q∝
(1/g) 2 , so by making the cross section of the pipe 12 horizontally elongated, g increases and the high frequency loss Q decreases, as shown in FIG.
（他の実施例）
第３図は本発明の他の実施例で、アンテナ前面
部のフアラデーシールド８のパイプ１２の断面形
状を示す。本実施例においては、パイプ１２間の
空〓が狭くなる様にフインを設けたものである。
これによつて、前に述べた例と同様に、アンテナ
とフアラデーシールドとの静電容量が増加するた
め、フアラデーシールドの高周波損失を低減する
ことができる。(Other Embodiments) FIG. 3 shows another embodiment of the present invention, showing the cross-sectional shape of the pipe 12 of the Faraday shield 8 on the front side of the antenna. In this embodiment, fins are provided so that the space between the pipes 12 becomes narrower.
This increases the capacitance between the antenna and the Faraday shield, as in the previous example, so that the high frequency loss of the Faraday shield can be reduced.
以上の説明のように、本発明ではアンテナの前
面部及び前面以外の部分に本発明の様な断面形状
のパイプを用いたので、フアラデーシールドに生
ずる高周波損失を低減することができる。従つ
て、温度上昇による熱応力が低減される。また、
アンテナの電圧を下げる効果によつて、アンテナ
の絶縁破壊の可能性が低下する。
As described above, in the present invention, since the pipe having the cross-sectional shape of the present invention is used in the front part of the antenna and the parts other than the front part, it is possible to reduce the high frequency loss occurring in the Faraday shield. Therefore, thermal stress due to temperature rise is reduced. Also,
The effect of lowering the voltage on the antenna reduces the possibility of dielectric breakdown of the antenna.
第１図および第２図は本発明のフアラデーシー
ルドの一実施例を示し第６図のそれぞれ１３ａ部
分および１３ｂ部分にあたる断面図、第３図は本
発明の他の実施例を示す断面図、第４図は本発明
のフアラデーシールドが用いられる核融合装置の
一部破断立面図、第５図は従来のフアラデーシー
ルドの一部破断斜視図、第６図および第７図はそ
れぞれ第５図の−線および−線に沿う断
面図である。
３……同軸管、４……プラズマ、５……結合
系、７……アンテナ導体、８……フアラデーシー
シド、１０……アンテナケーシング、１１……ジ
ヤケツト、１２……パイプ、１３ａ……パイプの
アンテナ前面部、１３ｂ……パイプのアンテナ前
面以外の部分、ｇ……フアラデーシールドのピツ
チ、Ｕ……フアラデーシールド間の空〓、１６…
…フイン。
1 and 2 are cross-sectional views showing one embodiment of the Faraday shield of the present invention, corresponding to portions 13a and 13b, respectively, in FIG. 6, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention. , FIG. 4 is a partially cutaway elevational view of a nuclear fusion device in which the Faraday shield of the present invention is used, FIG. 5 is a partially cutaway perspective view of a conventional Faraday shield, and FIGS. 6 and 7. are sectional views taken along lines - and - in FIG. 5, respectively. 3... Coaxial tube, 4... Plasma, 5... Coupling system, 7... Antenna conductor, 8... Farady seaside, 10... Antenna casing, 11... Jacket, 12... Pipe, 13a... ...The front part of the antenna of the pipe, 13b...The part of the pipe other than the front of the antenna, g...The pitch of the Faraday shield, U...The sky between the Faraday shields, 16...
...Fin.
Claims (1)
トロン周波数高周波加熱用のアンテナ導体との間
に設置され複数のパイプから成るフアラデーシー
ルドにおいて、前記パイプの前記アンテナ導体の
前面の部分はアンテナ導体に向きあう面をパイプ
相互に向きあう面よりも広くし、前記パイプの前
記アンテナ導体の前面以外の部分はアンテナ導体
に向きあう面をパイプ相互に向きあう面よりも狭
くしたことを特徴とするフアラデーシールド。1. In a Faraday shield consisting of a plurality of pipes installed between the plasma space of a fusion device and an antenna conductor for ion cyclotron frequency high-frequency heating, the front part of the antenna conductor of the pipe faces the antenna conductor. The faraday is characterized in that the surface of the pipe is wider than the surface that faces each other, and the surface of the pipe other than the front surface of the antenna conductor that faces the antenna conductor is narrower than the surface that faces the pipes. shield.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59205544A JPS6185799A (en) | 1984-10-02 | 1984-10-02 | Faraday shield |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59205544A JPS6185799A (en) | 1984-10-02 | 1984-10-02 | Faraday shield |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6185799A JPS6185799A (en) | 1986-05-01 |
| JPH0544995B2 true JPH0544995B2 (en) | 1993-07-07 |
Family
ID=16508648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59205544A Granted JPS6185799A (en) | 1984-10-02 | 1984-10-02 | Faraday shield |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6185799A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01186600A (en) * | 1988-01-13 | 1989-07-26 | Japan Atom Energy Res Inst | Faraday shield for high frequency heating device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6166400A (en) * | 1984-09-07 | 1986-04-05 | 日本原子力研究所 | Plasma heating antenna |
-
1984
- 1984-10-02 JP JP59205544A patent/JPS6185799A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6185799A (en) | 1986-05-01 |
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