共查询到19条相似文献,搜索用时 187 毫秒
1.
在简单磁镜MM-2中,在采用15GHz大功率迴旋管进行电子迴旋共振加热(ECRH)的同时,以不同的方式向磁镜中注入电子束,进行了ECRH捕获电子束的实验研究。结果表明:由于电子束的提前注入,等离子体的预电离时间被大大地缩短。由上ECRH对电子束的捕获,使得热电子环参数得到很大的改善,热电子环的反磁β值约增加62%,对应反磁增加的捕获效率约为(30—40)%。在迴旋管输出约30kW的条件下,适应建立热电环的气体压力窗为(4.67—21.3)×10-4Pa。
关键词: 相似文献
2.
用碘化钠探测器研究简单磁镜装置MM—2中热电子环特性 总被引:1,自引:1,他引:0
使用碘化钠(NaI)探测器,对MM-2简单磁镜装置中热电子环参数进行了测量,得到热电子温度为140—170keV,热电子环的半径为7cm,其径向厚度为4cm,轴向尺寸边缘区域从±10cm延伸至±20cm,同时也观测到了热电子密度沿径向分布,环的位置与磁场强度的关系以及硬X射线发射的时间特性。 相似文献
3.
利用同步辐射光电离质谱结合理论计算, 研究了异亮氨酸的真空紫外光诱导电离解离.在光子能量为13 eV的质谱中探测到了m/z=86、75、74、69、57、46、45、44、41、30、28、18的碎片离子.对于异亮氨酸的主要碎片离子为:C5H12N+ (m/z=86)、C2H5NO4+ (m/z=75)、C5H9+ (m/z=69)、C4H9+(m/z=57)和CH4N+(m/z=30).由光电离效率曲线得到出现势分别为:8.84±0.07、9.25±0.06、10.20±0.12、9.25±0.10、11.05±0.07 eV.结合量化理论计算(B3LYP/6-31++G(d,p)),详细给出了它们可能的生成路径.这些解离通道包括简单的键断裂反应和涉及中间体、过渡态的反应,实验值和理论计算的离子出现能或势垒一致. 相似文献
4.
5.
热电子环结构对阱深和贮能影响的分析 总被引:1,自引:1,他引:0
简单磁镜MM-2ECH实验产生的热电子环未能在磁镜中形成磁阱。反磁信号△V为15cmV时,热电子环垂直方向贮能W。为0.317J,最大β_(⊥,max)为1.6%,热电子环在中平面径向平均β⊥为0.9%。局域使增量△B为零,或使增量△∮dl/B为零所需热电子环的贮能W和β_(⊥,max)与热电子环结构(厚度、宽度和位置)有关。 相似文献
6.
本文在20°—300°K研究了室温载流子浓度2×1012—1×1020cm-3含硼或磷(砷)Si的电学性质。对一些p-Si样品用弱场横向磁阻法及杂质激活能法进行了补偿度的测定,并进行了比较。从霍尔系数与温度关系的分析指出,对于较纯样品,硼受主能级的电离能为0.045eV,磷施主能级为0.045eV,在载流子浓度为1018—1019cm-3时发现了费米简并,对载流子浓度为2×1017—1×1018cm-3的p-Si及5×1017—4×1018cm-3的n-Si观察到了杂质电导行为。从霍尔系数与电导率计算了非本征的霍尔迁移率。在100°—300°K间,晶格散射迁移率μ满足关系式AT-a,其中A=2.1×109,α=2.7(对空穴);或A=1.2×108,α=2.0(对电子)。另外,根据我们的材料(载流子浓度在5×1011—5×1020cm-3间),分别建立了一条电阻率与载流子浓度及电阻率与迁移率的关系曲线,以提供制备材料时参考之用。 相似文献
7.
8.
报道了在13.5—14.6MeV中子能区用活化法以93Nb(n,2n)92mNb反应截面为中子注量标准测得的150Nd(n,2n)149Nd,148Nd(n,2n)147Nd和142Nd(n,2n)141Nd的反应截面值.由13.5±0.2,14.1±0.1和14.6±0.2MeV中子引起的150Nd(n,2n)149Nd反应截面值分别为2037±85,1737±68,1657±65mb,148Nd(n,2n)147Nd反应截面值分别为1394±58,1416±54,1956±76mb,142Nd(n,2n)141Nd反应截面值分别为1501±59,1623±62,1764±111mb.单能中子由T(d,n)4He反应获得.文中还收集了已发表的数据以作比较. 相似文献
9.
报道了在13.5—14.6MeV中子能区用活化法测得的160Gd(n,2n)159Gd和158Gd(n,p)158Eu的
反应截面值. 中子注量用93Nb(n, 2n)92m Nb反应截面得到. 由(13.5±0.2)MeV,(14.1±0.1)MeV和(14.6±0.2)MeV中子引起的160Gd(n, 2n) 159Gd反应截面值分别为(1940±83)mb, (2324±92)mb和(1983±77)mb, 158Gd(n, p) 158Eu反应截面值分别为(1.9±0.1)mb, (2.1±0.1)mb和(3.5±0.1)mb. 单能中子由T(d, n)4He反应获得.文中还列举了已收集到的数据以作比较. 相似文献
10.
报道了在13.5—14.6MeV中子能区用活化法以93Nb(n,2n)92mNb反应截面为中子注量标准测得的69Ga(n,2n)68Ga,69Ga(n,p)69mZn,71Ga(n,p)71mZn和71Ga(n,n′α)67Cu的反应截面值.由(13.5±0.2),(14.1±0.1)和(14.6±0.2)MeV中子引起的69Ga(n,2n)68Ga反应截面值分别为(794±31),(869±35)和(986±39)mb,71Ga(n,n′α)67Cu反应截面值分别为(1.3±0.1),(1.7±0.1)和(2.5±0.1)mb.在中子能量为(14.1±0.1)MeV能量点,69Ga(n,p)69mZn反应截面值为(21.5±1.0)mb,71Ga(n,p)71mZn反应截面值为(12.4±0.7)mb.单能中子由T(d,n)4He反应获得.文中还列举了尽可能收集到的数据以作比较. 相似文献
11.
12.
VUV emission spectra of plasmas produced by focusing laser radiation with intensity of 1010–1011 W/cm2 on carbon and aluminum targets were studied. Using the partial local thermodynamic equilibrium model for an electron density exceeding 1017 cm?3, the spectroscopic diagnostics and the analysis of ion composition of plasmas were carried out. The electron temperatures determined for carbon and aluminum plasmas from the ratio of intensities of ionic lines were found to be 8±3 eV and 11±4 eV, respectively. Stark broadening of aluminum lines was measured and parameters of electron broadening were determined. Using the spatially resolved measurement of Stark line broadening, the spatial density distribution and the law of electron gas expansion were found. The electron gas in the hot region of size 5 mm with an average density of (5±2) 1017cm ?3 experienced one-dimensional expansion according to the law 1/z 1.1 with increasing distance z from the target. 相似文献
13.
K. Eidmann 《Zeitschrift für Physik A Hadrons and Nuclei》1970,238(2):189-194
The electron temperature has been measured in inductively coupled high frequency gas discharges in Ar, Kr and Xe with the aid of Langmuir probes. The measured temperature shows a rather low radial space dependence up to values ofpR ≈ 30 Torr cm (p=gas pressure,R=radius of the discharge vessel). This behaviour is explained on the basis of the local energy balance of the electrons as a consequence of the energy transport by thermal conduction in the electron gas. 相似文献
14.
M. Zelm 《Zeitschrift für Physik A Hadrons and Nuclei》1967,201(1):75-78
A swarm of electrons passing a KBr-crystal has been investigated by fast oscilloscopic techniques at high electric fields (3×104 to 4×105 V/cm). From the temporal current shape we determined the electron drift mobilityμ=15±2 cm2/Vsec, the electron life timeτ=2±0.3 × 10?7 sec and the multiplication factor. From this measurement the ionization coefficientα for electrons was calculated as a function of the applied electric field. 相似文献
15.
Y. Itoh 《International Journal of Infrared and Millimeter Waves》1984,5(8):1083-1101
An axisymmetric quasi-optical gyrotron (ASQUOTRON) is considered to realize a 10 MW, 150 GHz, CW oscillator required for an electron cyclotron resonance heating of a fusion plasma. The gyrotron has an axisymmetric mirror to be used as its optical cavity. It is shown that the axisymmetric mirror of relatively small radius (20 cm) can be used in producing the 10 MW continuous wave with a tolerable mirror heat load (0.5 kW/cm2). Considerations are also made on wave transmissions through the mirror and to a target. 相似文献
16.
J.?Sch?fer F.?Sigeneger R.?Foest D.?Loffhagen K.-D.?Weltmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):531-538
Electron temperature and electron concentration in the active zone of a miniaturized radio frequency (RF)
non-thermal atmospheric pressure plasma jet in argon
have been
determined using two independent approaches: the spectroscopic measurement of the broadening of Balmer
Hb_\beta and Hg_\gamma lines and a
time-dependent, spatially two-dimensional
fluid model of a single discharge filament.
The plasma source has been
configured as a capacitively coupled RF jet (27.12 MHz, 8 W generator output power)
with two outer ring electrodes around a quartz capillary
with diameter of 4.0 mm between which Ar flows at typical rates of 0.3 slm. The discharge has been
operated in a self-organized mode, where equidistant, stationary filaments rotate regularly with a constant frequency at the
inner
wall of the outer capillary.
For the purpose of calculating the spectral line broadening different models applicable at higher electron concentration have
been evaluated. Resulting electron concentrations are between 2.2 and 3.3 × 1014 cm-3. The calculation according to the
line broadening model provides electron temperatures
between 20 000 and 30 000 K which is in agreement with the results of the
fluid model calculations.
Here, a broad radial profile with a maximal value of about 22 000 K in the
centre of the column and an electron concentration of about 7 × 1013 cm-3
have been obtained.
Moreover, the results of the model calculations reveal
a structural change of the filament from the dielectric surface through the sheath to the column.
The axially inhomogeneous region has an extension of about 0.5 mm.
In the column a concentration of about 1013 cm-3 has been found
for the excited argon atoms, whose collisions with electrons represent
the most important ionization channel there. 相似文献
17.
利用强流电子束技术产生通量密度为1018—1019X-ray photon/sr·s的脉冲CuKX射线源,标定PIN型硅二极管半导体探测器对X光子的脉冲灵敏度。用绝对X射线监测器——P10气体脉冲电离室作为脉冲X射线通量密度的标准。脉冲电荷自动测量仪由微处理机进行程序控制,并予以实时校准。该电离室测量通量密度的精度为±5%,适用的能通量率范围可达4×10-9—2×102W/cm2,适用的光子能量范围为1.5—10keV,标定探测器的精度为±7.0%,并发现PIN型硅二极管的脉冲灵敏度比稳态X射线束标定的灵敏度高30%左右。
关键词: 相似文献
18.
A. Morozov T. Heindl J. Wieser R. Krücken A. Ulrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(1):51-57
Continuous and pulsed 12 keV electron beams were used to excite nitrogen
within a gas cell at pressures ranging from 10 to 1400 hPa. The pressure
dependence of the ratio of photon fluxes for emission from vibrational
levels v'=0 and 1 of the C 3Π u state has been studied. The
results confirm the presence of a collisional excitation mechanism
populating v'=0, 1 in addition to electron impact excitation. Rate constants
of (1.27 ±0.04)×10-11 cm3s-1 [ v'=0] and
(2.68 ±0.08)×10-11 cm3s-1 [ v'=1] were measured for
C 3Π u quenching by ground state nitrogen. For electron beam
conditions relative excitation efficiencies of 1:0.59:0.22 for
vibrational levels 0, 1 and 2 were calculated. The recorded flux ratios are
compared with the predictions given by a vibrational relaxation model. 相似文献
19.
Ling G. Piosczyk B. Thumm M.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(3):606-613
A feasibility study for a two-stage depressed gyrotron collector has been performed. A new approach for an adiabatic magnetic decompression of the hollow electron beam has been used. It permits control of the radius of the constant magnetic flux surface, which determines the radial extension of the electron beam. Independent of the value of the magnetic field around the beam. For this purpose, either solenoidal coils or a ferromagnetic insert can be placed inside the hollow electron beam. Thus, the radial dimensions of a multistage depressed collector of a high-power high-frequency gyrotron can be kept within limits given by technological constraints. The energy sorting of the electron beam is improved by using electrodes inside the hollow electron beam for controlling the potential distribution. The additional control electrodes make it possible to eliminate almost all of the effect of secondary electrons on the operation of the collector. In order to demonstrate the proposed approach, a compact two-stage depressed collector has been designed for a 1.5-MW coaxial cavity gyrotron operating at 165 GHz in the transverse electric (TE)31,17 mode, which is under development at FZK, Karlsruhe, Germany. Including the effect due to secondary electrons, a collector efficiency of 73% has been calculated with an average and peak heat dissipation density of about 240 W/cm2 and 500 W/cm2, respectively. This results in an increase of the output gyrotron efficiency from 36.5% to 62.6% when internal radio frequency (RF)-losses inside the gyrotron tube of 15% are taken into account 相似文献