Loading [MathJax]/jax/output/SVG/jax.js
Advanced Search+
Xinghua ZHANG, Zhenhua ZHANG, Shaoxia JIA, Ting JIN, Jinghua YANG, Long LI, Fangfang LIU, Yong CAI, Jian CAI. Influence of anode temperature on ignition performance of the IRIT4-2D iodine-fueled radio frequency ion thruster[J]. Plasma Science and Technology, 2022, 24(1): 015506. DOI: 10.1088/2058-6272/ac34e6
Citation: Xinghua ZHANG, Zhenhua ZHANG, Shaoxia JIA, Ting JIN, Jinghua YANG, Long LI, Fangfang LIU, Yong CAI, Jian CAI. Influence of anode temperature on ignition performance of the IRIT4-2D iodine-fueled radio frequency ion thruster[J]. Plasma Science and Technology, 2022, 24(1): 015506. DOI: 10.1088/2058-6272/ac34e6

Influence of anode temperature on ignition performance of the IRIT4-2D iodine-fueled radio frequency ion thruster

More Information
  • Author Bio:

    Jian CAI: E-mail: caijian@ime.ac.cn

  • Received Date: June 26, 2021
  • Revised Date: October 24, 2021
  • Accepted Date: October 28, 2021
  • Available Online: March 18, 2024
  • Published Date: December 07, 2021
  • This paper reports the ignition performance of the iodine-fueled radio frequency (RF) ion thruster (IRIT) at different anode temperatures (Ta0). The experimental results show that the anode temperature plays important role on the ignition process of the IRIT. There were two characteristic temperatures related to the anode: the minimum ignition temperature (Ti0) and the stable ignition temperature (Tis), which were much lower than the pipeline temperature and the storage tank temperature. At Ta0<Ti0, it failed to discharge. When Ti0Ta0<Tis, it was ignited with dramatical oscillations. At Ta0Tis, the discharge was stable in a large anode temperature range. The analysis showed that the different discharge phenomena at different anode temperatures were attributed to the change of iodine flow rate during the process of the iodine deposition-clogging and sublimation-clearing inside the thruster. The research helps improve the preheating design of the iodine-fueled electric thruster.

  • The Ion Cyclotron Radio Frequency (ICRF) heating antenna adopts the design of multi-radiation straps, which results in a strong power coupling between the straps [17]. To restrain such power coupling, variable decouplers have been developed in the world tokamak machines [813], and a decoupler based on the T-shape shorted stub was used on EAST [1417]. However, during the experiment, it was discovered that the short-circuit type with piston had shortcomings such as long size, difficult to adjust electrical length, poor contact of the short-circuit finger which leads to easy burning out etc. Therefore, it is planned to adopt a terminal-loaded tunable capacitor solution to shorten the length of the stub and facilitate adjustment, and the design of none short-circuit contact finger can avoid the problem of poor contact and burnout.

    The design of a decoupler with terminal-loaded tunable capacitors should meet the requirements of mutual coupling suppression on EAST antennas, which works under the pressurized atmosphere of the transmission line. By changing the capacitance value, the imaginary part of non-diagonal term of Y parameter of the decoupler is supposed to achieve |YT12/T21|5×10-4S [16]. In addition, the compactness and feasibility of the structure, the withstand voltage and the tunable range of the capacitor and other factors also need to be considered during the process of system design.

    Three significant aspects are elaborated: T-shape stub with tunable capacitor design, simulation analysis and physical test. Section 2 introduces the theoretical derivation of the admittance matrix of the decoupling device, the relationship among the capacitor voltage and the capacitance value, and so on. Section 3 builds a simulation model based on the design parameters and discusses the simulation results. Section 4 shows the test results of the developed system without plasma. Finally, there is a conclusion of the whole design and tests.

    Besides the tunable admittance parameters of decoupler, the withstand voltage of the capacitor is the most significant consideration for decoupler to work under high power. Therefore, based on the microwave engineering theory, the calculation model of capacitor loaded decoupler is constructed, and the capacitor working voltage and other performance parameters are deduced theoretically, which will be the foundation of the parameter's selection of decoupler.

    Based on the original design [16], only the change of the introduced part of capacitive loading needs to be considered. Two-port network design with T-shape structure is applied on the decoupler. One of the ports is loaded with a terminal short-circuit tunable vacuum capacitor, as shown in figure 1(a). The T-shape stub loaded with tunable capacitor circuit used in decoupler can be equivalent to a two-port network cascaded by three parts, as shown in figure 1(b). The cascaded three parts are transmission line L1, L2 and T-shape stub respectively, where the ABCD matrix of transmission line L1 and L2 can be expressed as:

    A1=[cosβlj×sinβlY0j×sinβl×Y0cosβl], (1)
    Figure  1.  (a) Equivalent model of decoupler, (b) equivalent circuit of decoupler.

    where, β is phase constant, l is the length of transmission line L1 and L2. Because of symmetrical design, L1=L2=l. Y0 is the characteristic admittance of transmission line.

    The ABCD matrix of part 2, i.e. T-shape stub, is: A2=[10Yd1], where Yd can be expressed as [18]:

    Yd=1Zd=-j×Y0cot(βd-θ), (2)
    θ=tan-1(1ωCZ0). (3)

    Among them, Zd and Yd are the impedance and the admittance of the T-shape stub, θ is the equivalent phase of the capacitor, ω is the operating angular frequency, C is the capacitance of the capacitor.

    According to microwave transmission theory, the ABCD matrix of decoupler can be expressed as: A=A1×A2×A1, and according to the conversion relationship of Y matrix and ABCD matrix, the Y matrix of decoupler can be derived as:

    YT=[YT11YT12YT21YT22], (4)

    where

    YT11=YT22=j×Y0×Yd×sinβl×cosβl-Y02×(sinβl)2+Y02×(cosβl)2(-Yd)×(sinβl)2+j×2×Y0×sinβl×cosβlYT12=YT21=-Y02(-Yd)×(sinβl)2+j×2×Y0×sinβl×cosβl. (5)

    Therefore, the diagonal admittance of decoupler is determined by the equivalent phase of the terminal-loaded capacitor, which is the foundation for the decoupler to perform the mutual coupling suppression.

    When the capacitor is loaded at the short-circuit end of the T-shape stub, the withstand voltage and the tunable capacitance value need to be considered for high-power operation and antenna decoupling. The voltage at both ends of decoupler is: Vm=[V1V2], then, the current can be expressed as: [I1I2]=YT×Vm. According to the relationship between ABCD matrix and voltage-current, it can be deduced that Vd is as follow:

    Vd=V1×cosβl-j×sinβlY0×(V1×YT11+V2×YT12). (6)

    T-shape stub with terminal loaded capacitor can be expressed as figure 2, d is the fixed length of transmission line before loaded capacitor, Z0 is characteristic impedance of transmission line. The voltage of loaded capacitor can be sustained by the voltage propagation equations of a terminated transmission line [18], which is:

    Vc=Vde-jβd1+ΓL1+Γd, (7)
    Figure  2.  Diagram of the T-shape stub.

    where, ΓL=Zc-Z0Zc+Z0,Γd=Zd-Z0Zd+Z0,Zc=1jωC.

    Based on equations (4) and (7), the known parameters and conditions can be brought in to design the withstand voltage and capacitance value of the tunable capacitor. According to the design requirements and test conditions of ICRF antenna, the parameters already known are as follows:

    (1) Operating frequency f=37MHz;

    (2) Design requirements according to experimental statistics [16]: |Im(YT21)|5×10-4S;

    (3) Length selection of T-shape stub: L1=L2=λ4;

    (4) Port voltage at the hard-fed connection between T-shape stub and ICRF antenna: V1=V2=30kV;

    (5) According to tunable capacitor selection manual [19], the operating voltage amplitude of the capacitor: |Vc|30kV,and the range of C is: 60pFC1000pF, so as to ensure the compactness of branch d.

    Put condition (3) into equation (4) to derive:

    YT12=Y20Yd=j×Y0tan(βd-θ). (8)

    According to equation (7), it can be deduced that:

    Vc=Vde-jβd1-jcot(βd-θ)1+jωCZ0. (9)

    To satisfy design requirement (2), the range of tan(βd-θ) can be derived from equation (8) that:

    -0.025tan(βd-θ)0.025. (10)

    Taking three significant digits after the decimal point, atan(0.025)0.025, atan(-0.025)-0.025, and tan function takes π as the period, then solve equation (10) to obtain:

    -0.025+n×πβd-θ0.025+n×π, n is an integer.

    According to known condition (5), the range of capacitor C is: 60pFC1000pF, the equivalent electric phase can be derived: 0.0858θ0.9618. In order to make d length of T-shape stub as compact as possible, the value of n is set to be 0, so:

    -0.025βd-θ0.025. (21)

    According to equation (9), the voltage of the tunable capacitor can be calculated under different values of d, as shown in figure 3. It is shown that the absolute value of capacitor voltage Vc decreases as C increases, i.e. when the capacitance value of the tunable capacitor is larger, the voltages withstand condition of the capacitor itself will be significantly improved.

    Figure  3.  Relationships between voltage Vc of capacitor and capacitance of C.

    However, when the capacitance value C of the tunable capacitor is greater, in order to achieve the corresponding parallel admittance YT21 required, the length of d will become shorter, and the structural implementation will become more difficult. Taking YT21 into account, the working parameters d=450mm, 220pFC260pF are determined. At this time, the tunable range of T-shape stub is |Im(YT21)|<5×10-4S, and the capacitance voltage Vc is 19–22 kV, as shown in figure 4.

    Figure  4.  Admittance YT12 and voltage Vc with different capacitance C of the capacitor.

    According to these parameters, the capacitor CKTB1000/35/25 produced by Kunshan Guoli Electronic Technology Co., which can achieve the tunable capacitance of 60-1000pF with the maximum voltage of 30 kV, is selected [19]. Simulation models are built based on this capacitor, as shown in figure 5. Through the optimization of the length d and capacitor C, the result achieved shows that when d=450mm, and 163pFC183pF, it can realize the design requirements of capacitor voltage Vc30kV, and Im(YT21) can be tuned within |Im(YT21)|5×10-4S, as shown in figure 6. The capacitor voltage is 22.6kVVc23.7kV with the |Im(YT21)|<5×10-4S.

    Figure  5.  (a) 3D modeling of T-shape stub loaded capacitor, (b) electric field distribution of loaded capacitor in the T-shape stub.
    Figure  6.  Working diagram of capacitor voltage Vc, admittance YT12 and capacitor C at the operating frequency of 37MHz.

    In order to make Im(YT21) meet the tunable requirement of (|Im(YT21)|5×10-4S), there are differences between the analytical calculation results shown in figure 4 and the 3D model simulation results shown in figure 6. The results of analytical calculation showed that d=450mm and the tunable range of capacitance C was 220pFC260pF with the operating voltage of 19kVVc22kV. However, the results of 3D simulation showed that d=450mm and the tunable range of capacitance C was 163 pFC183pF with the operating voltage of 22.6kVVc23.7kV. The reason for the difference is that there is parasitic capacitance and inductance inside and outside the capacitor. In figure 5, the lumped capacitor is set between the capacitor and the outer conductor and there is also an electric field distribution, which induces the additional parasitic capacitance and inductance. In addition, it can also be found that the influences of other parasitic factors, such as parasitic capacitance and inductance introduced by the discontinuity of capacitor connector, have caused the appeal deviation. As a result, the actual withstand voltage of the capacitance maybe exceed the calculated value, which should be noted in experiments. In practice, after the capacitor is adjusted to the decoupling working point, its capacitance can be measured again to check its withstand voltage.

    Considering the achievability of the structure of d-length, theoretical calculation parameters adopted finally are: L1 and L2 take 1/4 wavelength of 2143 mm, d is 450 mm, and the model of capacitor is CKTB1000/35/250. The test adapters are selected at the ports of T-shape stub connector, as shown in figure 7(a). From the perspective of structural size, the previous design of the sliding stub is ~5 m long, as shown in figure 7(b), and tune of electrical length is achieved by mechanical sliding of short-circuit terminal. When the size is too long, it is quite difficult to guarantee the concentricity effectively. So, there is an obvious risk of damage to the short-circuit contact fingers with high-power operation, as found in previous experiments. Besides, the application of vacuum capacitors effectively reduces the size of the decoupler, which has obvious advantages when building the decoupling network for an ICRF multi-strap antenna.

    Figure  7.  (a) Capacitor-loaded T-shape stub, (b) T-shape stub with mechanical sliding of short-circuit terminal.

    Compared with T-shape stub, the difference of decoupler is L1/2-450mm in transmission line length at two ports, so the decoupler admittance can be obtained by measuring T-shape stub and transforming it by microwave networks analysis, as shown in figure 8. The test results of parallel admittance Im(YT21) of decoupler meet the required tunable range of (|Im(YT21)|5×10-4S). In the working region of capacitor, there is a certain linear relationship between capacitance regulation and admittance change, which is in line with the theoretical analysis in section 2. In addition, the admittance of the decoupler has a very wide tune range, which means that it can be used as a general design solution for various ICRF antennas. However, from the theoretical analysis, it is known that the choice of the working capacitance directly determines the working voltage and high-power stability of the capacitor, which needs to be considered in actual usage and has been described in the above theoretical analysis and analytical solution.

    Figure  8.  Test data of YT12/T21 of T-shape stub and decoupler.

    In EAST 2021 experiments, the decoupler with this new design is adopted for two straps ICRF antenna at port N. The scattering parameter S21 of the two ports without plasma tested by a vector network analyzer is optimized from –22 to –58 dB at the working frequency of 37 MHz, as shown in figure 9. Due to the influence of plasma discharge parameters, the adjustable capacitance will be fine-tuned between shots for compensation. Usually, the fine-tuning range is very fine. For coaxial adjustable capacitors, it does not exceed the adjustment range of one circumference. Then a limit signal can be used to overcome the difficulty of coaxial adjustable capacitor in capacitance calibration. Based on above reasons, this design of capacitor-loaded decoupler satisfies the requirements of compactness and remote adjustability for ICRF decoupling network on EAST.

    Figure  9.  Scattering parameter S21 before and after decoupling at 37 MHz.

    During the design of capacitor-loaded decoupler, those factors, such as the adjustable range of parallel admittance, the compactness and feasibility of the structure, and the voltage and adjustable range of the capacitor, have been taken into considerations. The theoretical analysis carefully elaborates the capacitor withstand voltage, which is the most significant aspect for high power operation of decoupler, and the detailed analytical equations and criteria for design are given. The test results show that the imaginary part of YT21 covers |Im(YT21)|5×10-4S. The capacitor-loaded decoupler has been successfully adopted for ICRF antenna at port N on EAST, and achieved the optimization from -22 to -58 dB at 37 MHz without plasma. The new design of the decoupler has greatly improved its compactness and automatic tune performance, and could be good solution for the decoupling network of ICRF antennas.

    The financial support from National Natural Science Foundation of China (No. 11805265) and Key Laboratory of Micro-Satellites, Chinese Academy of Sciences (No. KFKT201903) is gratefully acknowledged.

  • [1]
    Dressler R A, Chiu Y H and Levandier D J 2000 Propellant alternatives for ion and hall effect thrusters Proc. of the 38th Aerospace Sciences Meeting and Exhibit (Reno, NV: AIAA)
    [2]
    Tverdokhlebov O S and Semenkin A V 2001 Iodine propellant for electric propulsion-to be or not to be Proc. of the 37th Joint Propulsion Conf. and Exhibit (Salt Lake City, UT, USA: AIAA)
    [3]
    Szabo J et al 2012 J. Propul. Power 28 848 doi: 10.2514/1.B34291
    [4]
    Szabo J et al 2015 IEEE Trans. Plasma Sci. 43 141 doi: 10.1109/TPS.2014.2367417
    [5]
    Szabo J et al 2017 Characterization of a one hundred watt long lifetime hall effect thruster for small spacecraft AIAA Propulsion and Energy Forum, 53rd AIAA/SAE/ASEE Joint Propulsion Conf. (Atlanta, GA)
    [6]
    Kamhawi H et al 2016 Overview of iodine propellant hall thruster development activities at NASA Glenn Research Center American Institute of Aeronautics and Astronautics, 52nd AIAA/SAE/ASEE Joint Propulsion Conf.
    [7]
    Smith T D et al 2016 Overview of NASA iodine hall thruster propulsion system development In: https://ntrs.nasa.gov/search.jsp?R=20160006296
    [8]
    Liu H et al 2019 J. Propul. Technol. 40 12 (in Chinese)
    [9]
    Tsay M, Frongillo J and Hohman K 2015 Iodine-fueled Mini RF ion thruster for CubeSat applications Proc. of the 34th Int. Electric Propulsion Conf. and 6th Nano-satellite Symp (Hyogo-Kobe, Japan: IEPC)
    [10]
    Tsay M et al 2017 Integrated testing of iodine BIT-3 RF ion propulsion system for 6U CubeSat applications The 35th Int. Electric Propulsion Conf. (USA: Georgia Institute of Technology)
    [11]
    Holste K et al 2018 Eur. Phys. J. D 72 9 doi: 10.1140/epjd/e2017-80498-5
    [12]
    Martínez J M, Rafalskyi D and Aanesland A 2019 Development and testing of the NPT30-I2 iodine ion thruster 36th Int. Electric Propulsion Conf. (Vienna, Austria: University of Vienna)
    [13]
    Yang J H et al 2020 Plasma Sci. Technol. 9 094006 doi: 10.1088/2058-6272/ab891d
    [14]
    Manente M et al 2019 REGULUS: iodine fed plasma propulsion system for small satellites 36th Int. Electric Propulsion Conf. (Vienna, Austria: University of Vienna) IEPC-2019-417
    [15]
    Manente M et al 2019 REGULUS: know-how acquired on iodine propellant 36th Int. Electric Propulsion Conf. (Vienna, Austria: University of Vienna) pp 1–10 IEPC- 2019-419
    [16]
    Polzin K A 2018 Iodine satellite propellant feed clog-clearing demonstration testing In: NASA/TM—2018–220128.1-28
    [17]
    Samples S A, Dankanich J W and Polzin K A 2015 Iodine hall thruster feed system design, development and testing 51st AIAA/SAE/ASEE Joint Propulsion Conf. (Orlando, FL: AIAA)
    [18]
    Paganucci F et al 2019 I2HET: development of an iodine-fed hall effect thruster 36th Int. Electric Propulsion Conf. (Vienna, Austria: University of Vienna)
    [19]
    Li L et al 2020 Development of IRIT3.5-2D iodine-fueled ion electric propulsion system 16th China Electric Propulsion Symp. (Beijing, China) (in Chinese)
  • Related Articles

    [1]Jinghua YANG (杨景华), Shaoxia JIA (贾少霞), Zhenhua ZHANG (张振华), Xinghua ZHANG (张兴华), Ting JIN (金婷), Long LI (李龙), Yong CAI (蔡勇), Jian CAI (蔡建). Performance of a 4 cm iodine-fueled radio frequency ion thruster[J]. Plasma Science and Technology, 2020, 22(9): 94006-094006. DOI: 10.1088/2058-6272/ab891d
    [2]Xiuquan CAO (曹修全), Deping YU (余德平), Yong XIANG (向勇), Chao LI (李超), Hui JIANG (江汇), Jin YAO (姚进). Study on the ignition process of a segmented plasma torch[J]. Plasma Science and Technology, 2017, 19(7): 75404-075404. DOI: 10.1088/2058-6272/aa62f9
    [3]A F POPOVICH, V G RALCHENKO, V K BALLA, A K MALLIK, A A KHOMICH, A P BOLSHAKOV, D N SOVYK, E E ASHKINAZI, V Yu YUROV. Growth of 4″ diameter polycrystalline diamond wafers with high thermal conductivity by 915 MHz microwave plasma chemical vapor deposition[J]. Plasma Science and Technology, 2017, 19(3): 35503-035503. DOI: 10.1088/2058-6272/19/3/035503
    [4]DONG Yunsong (董云松), YANG Jiamin (杨家敏), SONG Tianming (宋天明), ZHU Tuo (朱托), HUANG Chengwu (黄成武). Radiation Hydrodynamic Simulations in the Planar Scheme for the Fundamental Studies of Shock Ignition[J]. Plasma Science and Technology, 2016, 18(4): 376-381. DOI: 10.1088/1009-0630/18/4/08
    [5]Hadar MANIS-LEVY, Tsachi LIVNEH, Ido ZUKERMAN, Moshe H. MINTZ, Avi RAVEH. Effect of Radio-Frequency and Low-Frequency Bias Voltage on the Formation of Amorphous Carbon Films Deposited by Plasma Enhanced Chemical Vapor Deposition[J]. Plasma Science and Technology, 2014, 16(10): 954-959. DOI: 10.1088/1009-0630/16/10/09
    [6]WU Maoshui(吴茂水), XU Yu(徐雨), DAI Linjun(戴林君), WANG Tiantian(王恬恬), LI Xue(李雪), WANG Dexin(王德信), GUO Ying(郭颖), DING Ke(丁可), HUANG Xiaojiang(黄晓江), SHI Jianjun(石建军), ZHANG Jing(张菁). The Gas Nucleation Process Study of Anatase TiO 2 in Atmospheric Non-Thermal Plasma Enhanced Chemical Vapor Deposition[J]. Plasma Science and Technology, 2014, 16(1): 32-36. DOI: 10.1088/1009-0630/16/1/07
    [7]MIAO Chunguang (苗春光), WANG Xiangqin (王相勤). Mass Deposition, Etching and Sputtering Effects of Low-Energy N + Ion Irradiation on Solid Fly Ash[J]. Plasma Science and Technology, 2013, 15(12): 1232-1236. DOI: 10.1088/1009-0630/15/12/13
    [8]YAN Ying (燕颖), CAI Kaiyong (蔡开勇), YANG Weihu (杨维虎), LIU Peng (刘鹏). Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors[J]. Plasma Science and Technology, 2013, 15(7): 648-653. DOI: 10.1088/1009-0630/15/7/09
    [9]M. MAHDAVI, A. GHOLAMI. Ignition Conditions for Simulated Fuel Pellets in Degenerate Plasma[J]. Plasma Science and Technology, 2013, 15(4): 323-328. DOI: 10.1088/1009-0630/15/4/04
    [10]CHEN Ju (陈聚), YAN Rong (鄢容), CHEN Junling (陈俊凌). Influence of Erosion and Deposition on Metallic First Mirror in HT-7 Tokamak[J]. Plasma Science and Technology, 2012, 14(8): 708-711. DOI: 10.1088/1009-0630/14/8/05

Catalog

    Figures(11)  /  Tables(1)

    Article views (124) PDF downloads (119) Cited by()

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return
    Return