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1.
N. I. Arkhipov V. P. Bakhtin S. G. Vasenin A. M. Zhitlukhin V. M. Safronov D. A. Toporkov 《Plasma Physics Reports》2001,27(3):228-234
Time-resolved measurements of quartz erosion are carried out to determine the density of the energy flux incident onto the
sample surface. These data are needed to create a reliable code describing the interaction of a thermonuclear plasma with
a solid surface. Experiments were performed in the 2MK-200 facilityunder the program of modeling heat loads on divertor plates
during disruptions in tokamaks. A 10-mm-thick plate of fused quartz was exposed to a high-temperature deuterium-plasma stream
with the temperature T
i
+T
e
≤1 keV, density (5–10)×1015 cm−3 β=0.25, energy density up to 200 J/cm2, and power density ∼10 MW/cm2. It is shown that the quartz erosion begins almost immediately after the stream reaches the surface. The eroded material
shields the quartz surface from further destruction. Under the given experimental conditions, the integral shielding factor
(the ratio of the stream energy to the energy reaching the surface) was rather high (about seventeen). As a result, at a stream
energy density of ∼150 J/cm2, the total erosion depth was about 0.75 μm over 35 μs. Based on the measured time dependence of the erosion depth and the
reference data on the thermal conductivity of the fused quartz, the power density incident onto the quartz sample was numerically
calculated.
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Translated from Fizika Plazmy, Vol. 27, No. 3, 2001, pp. 243–250.
Original Russian Text Copyright ? 2001 by Arkhipov, Bakhtin, Vasenin, Zhitlukhin, Safronov, Toporkov. 相似文献
2.
Yu. L. Bakshaev P. I. Blinov S. A. Dan'ko M. I. Ivanov D. Klír V. D. Korolev J. Kravárik J. Krása P. Kubeš V. I. Tumanov A. S. Chernenko A. V. Chesnokov A. Yu. Shashkov L. Juha 《Plasma Physics Reports》2002,28(6):472-478
Results are presented from the studies of the magnetic implosion of a tungsten wire liner onto an aluminum wire at currents
of 2.0–2.6 MA. The experiments were carried out in the S-300 high-power pulsed facility at the Russian Research Centre Kurchatov
Institute. The liner is composed of 50 wires 6 μm in diameter and 1 cm in length, which are equally spaced on a circle 1 cm
in diameter. An aluminum wire 120 μm in diameter is positioned at the array axis. The liner implosion was accompanied by the
generation of VUV and soft X-ray emission. The parameters of the pinch plasma produced during the liner implosion onto the
aluminum wire were determined from the time-resolved spectral measurements by a five-channel polychromator. The ion and electron
densities turned out to be equal to n
i≈4×1019 cm−3 and n
e≈4×1020 cm−3, respectively, and the electron temperature was T
e≈40 eV. The radiation energy measured in the range 50–600 eV was 2–10 kJ. The sources of soft X-ray emission in hydrogen-and
helium-like aluminum lines were the bright spots and local objects (clouds) formed in the plasma corona at an electron temperature
of 200–500 eV and electron density of 1021–1022 cm−3. The possibility of both the generation of an axial magnetic field during the liner implosion and the conversion of the energy
of this field into soft X-ray emission is discussed.
__________
Translated from Fizika Plazmy, Vol. 28, No. 6, 2002, pp. 514–521.
Original Russian Text Copyright ? 2002 by Bakshaev, Blinov, Dan'ko, Ivanov, Klír, Korolev, Kravárik, Krása, Kubeš, Tumanov,
Chernenko, Chesnokov, Shashkov, Juha. 相似文献
3.
Yu. L. Bakshaev P. I. Blinov V. V. Vikhrev E. M. Gordeev S. A. Dan’ko V. D. Korolev S. F. Medovshchikov S. L. Nedoseev E. A. Smirnova V. I. Tumanov A. S. Chernenko A. Yu. Shashkov 《Plasma Physics Reports》2001,27(12):1039-1047
The development of a preformed constriction in cylindrical agar-agar loads at currents of up to 3 MA is studied experimentally.
The loads 3–5 mm in diameter have a mass density of 0.1 g/cm3 and are filled with different materials. Due to the implosion of the constriction to a minimum size of 40–70 μm, a hot dense
plasma (with the electron density n
e=1022 cm−3, electron temperature T
e=0.8–1.5 keV, and ion temperature T
i=3–12 keV) is produced. It is found that the ion temperature substantially exceeds the electron temperature. The lifetime
of the high-temperature plasma determined from the FWHM of a soft X radiation (SXR) pulse is shorter than 5 ns, the radiation
power of photons with energies of ≥1 keV is higher than 0.5×1010 W, and their total energy attains 50 J. High-speed photography in the VUV, SXR, and optical spectral regions indicates the
protracted generation of the high-temperature plasma. Calculations by the two-dimensional ideal MHD model of the Z-pinch show
that the most important consequence of the protracted plasma generation in the constriction region is that the current is
intercepted by a freshly produced plasma. In the course of plasma generation, the current near the axis inside the region
of radius 50 μm is at most one-half of the total current. After the plasma generation comes to an end, almost the entire current
is concentrated in this region for several nanoseconds; this process is accompanied by a sharp increase in the plasma temperature.
__________
Translated from Fizika Plazmy, Vol. 27, No. 12, 2001, pp. 1101–1110.
Original Russian Text Copyright ? 2001 by Bakshaev, Blinov, Vikhrev, Gordeev, Dan’ko, Korolev, Medovshchikov, Nedoseev, Smirnova,
Tumanov, Chernenko, Shashkov. 相似文献
4.
The ion recombination times, the energy balance characteristics, and the time behavior of the radiation intensity of lead and gallium laser plasmas are determined by analyzing the trailing edges of the waveforms of various spectral lines. Reasons for different decay rates of the spectral lines are analyzed. Experiments on laser erosion of lead and gallium targets under the action of repetitive neodymium laser radiation with a pulse duration of 20 ns, wavelength of 1.06 μm, repetition rate of 12 Hz, and peak intensity on the target surface of 108–109 W/cm2 were carried out at a residual air pressure of 3–12 Pa. 相似文献
5.
Squirrel monkeys (Saimiri sciureus) trained to regulate environmental temperature (Ta) behaviorally were exposed in the far field of a horn antenna to ten-minute periods of 2,450 MHz CW microwaves. Incident power density ranged from 1 to 22 mW/cm2. The corresponding specific absorption rate (SAR), derived from temperature increments in saline-filled styrofoam models, ranged from 0.15 to 3.25 W/kg. Controls included exposure to infrared radiation of equivalent incident energy and no radiation exposure. Normal thermoregulatory behavior produces tight control over environmental and body temperatures; most monkeys select a Ta of 34–36°C. Ten-minute exposures to 2,450 MHz CW microwaves at an incident power density of 6–8 mW/cm2 stimulated all animals to select a lower Ta. This threshold energy represents a whole-body SAR of 1.1 W/kg, about 20% of the resting metabolic rate of the monkey. Thermoregulatory behavior was highly efficient, and skin and rectal temperatures remained stable, even at 22 mW/cm2 where the preferred Ta was lowered by as much as 4°C. No comparable reduction in selected Ta below control levels occurred during exposure to infrared radiation of equal incident power density. 相似文献
6.
E. A. Bolkhovitinov B. L. Vasin S. Yu. Gus’kov I. Ya. Doskach A. A. Erokhin B. V. Kruglov M. V. Osipov V. N. Puzyrev V. B. Rozanov A. A. Rupasov V. B. Studenov S. I. Fedotov L. P. Feoktistov A. S. Shikanov O. F. Yakushev 《Plasma Physics Reports》2004,30(2):183-186
The formation of craters in targets of various materials under the action of a high-power neodymium-laser pulse at radiation intensities from 1010 to 1014 W/cm2 was studied experimentally and theoretically. The interaction between the laser beam and solid targets is investigated to determine the efficiency of the ablation loading of various materials and the transformation of the laser energy into the energy of a shock wave. 相似文献
7.
In measuring the charge and energy spectra of the ions of a single-element laser plasma, in addition to thermal ions, fast multicharged ions are recorded that are accelerated by the electric field of laser radiation in the region of the critical plasma density. The charge and energy spectra of Co ions with the charge numbers z=1–3 are measured at laser intensities of q=5×1011–1012 W/cm2. The energy spectra of these ions are broad and are located on the high-energy side (z max=3, E>5.0 keV) with respect to the thermal ions (z max=9, E<4.0 keV). The increase in q to 1014 W/cm2 results in an increase in the charge number of both thermal and fast ions. 相似文献
8.
G. M. Batanov V. D. Borzosekov L. V. Kolik E. M. Konchekov D. V. Malakhov A. E. Petrov K. A. Sarksyan V. D. Stepakhin N. K. Kharchev 《Plasma Physics Reports》2017,43(11):1052-1064
Correlation between short-wavelength (k⊥ ≈ 20–30 cm–1) and long-wavelength (k⊥ ≈ 1–2 cm–1) plasma density fluctuations in two poloidal cross sections of the stellarator chamber separated by 1/14 or 5/14 of the torus perimeter was studied using collective scattering of radiation of two 75-GHz gyrotrons and radiation of a 37-GHz Doppler reflectometer at an ECR heating power density of 1.6–3.2 MW/m3. It is found that excitation of turbulent fluctuations is bursty in character and that fluctuations excited in different L-2M cross sections are uncorrelated. It is shown that the energy of turbulent fluctuations is modulated by a low frequency of 5–20 kHz. An idea is put forward that anomalous transport is toroidally inhomogeneous. 相似文献
9.
Satoshi Kajiyama Lucie Szabova Hiroki Iinuma Akira Sugahara Kazuma Gotoh Keitaro Sodeyama Yoshitaka Tateyama Masashi Okubo Atsuo Yamada 《Liver Transplantation》2017,7(9)
Pseudocapacitance is a key charge storage mechanism to advanced electrochemical energy storage devices distinguished by the simultaneous achievement of high capacitance and a high charge/discharge rate by using surface redox chemistries. MXene, a family of layered compounds, is a pseudocapacitor‐like electrode material which exhibits charge storage through exceptionally fast ion accessibility to redox sites. Here, the authors demonstrate steric chloride termination in MXene Ti2CTx (Tx : surface termination groups) to open the interlayer space between the individual 2D Ti2CTx units. The open interlayer space significantly enhances Li‐ion accessibility, leading to high gravimetric and volumetric capacitances (300 F g?1 and 130 F cm?3) with less diffusion limitation. A Li‐ion hybrid capacitor consisting of the Ti2CTx negative electrode and the LiNi1/3Co1/3Mn1/3O2 positive electrode displays an unprecedented specific energy density of 160 W h kg?1 at 220 W kg?1 based on the total weight of positive and negative active materials. 相似文献
10.
P. A. Tolstoukhov D. A. Vikhlyaev D. S. Gavrilov A. G. Kakshin E. A. Loboda V. A. Lykov V. Yu. Politov A. V. Potapov V. A. Pronin V. N. Saprykin K. V. Safronov 《Plasma Physics Reports》2011,37(10):866-870
Results from experimental studies of bremsstrahlung and characteristic radiation spectra from laser targets irradiated with ultrashort laser pulses with intensities of up to ~1019 W/cm2 are presented. The continuous spectra of hard X-ray emission from Ta and Al targets and the line spectrum of copper were measured. The temperature of fast electrons was obtained from the measured hard X-ray spectra, and the Kα radiation yield from Ta was measured. The energy conversion efficiency of laser radiation into the copper characteristic radiation was obtained from the measured yield of Kα radiation. 相似文献
11.
The plasma parameter studies of the Nd:YAG (neodymium-doped yttrium aluminum garnet, Nd:Y3Al15O12) crystal by using the fundamental (1064 nm) and second (532 nm) harmonics of Nd:YAG laser are reported. The electron temperature (T e ) and electron number density (N e) were determined using the Boltzmann plot method and the Stark-broadened line profile, respectively. An increase in the plasma parameters have been observed with an increase in the laser irradiance for both laser modes. The electron temperatures were calculated in the range of 0.53–0.66 eV for 1064 nm and 0.47–0.60 eV for 532 nm, and the electron number densities were determined in the range of 7.43 × 1015–3.27 × 1016 cm?3 for 1064 nm and 1.35 × 1016–3.97 × 1016 cm?3 for 532 nm in the studied irradiance range of 1.19–12.5 GW/cm2. However, the spatial evolution of the plasma parameters investigated up to 2.75 mm away from the target surface at a fixed laser irradiance of 6.51 GW/cm2 showed a decreasing trend. In addition, the estimated values of the inverse bremsstrahlung (IB) absorption coefficients at both laser wavelengths showed that the IB process is dominant for the 1064-nm laser. 相似文献
12.
It was shown theoretically that the increase in the cathode emission current in a low-voltage cesium-hydrogen discharge to ≈10 A/cm2 leads to an increase in the electron temperature in the anode plasma to T e ≥ 1 eV. In this regime, the rate constant for the production of H? ions via dissociative electron attachment to vibrationally excited H2 molecules is close to its maximum value and the density of H? ions is maximal (about 1013 cm?3) in the anode plasma. 相似文献
13.
G. N. Dudkin B. A. Nechaev V. N. Padalko V. M. Bystritsky V. A. Stolupin Vit. M. Bystritskii J. Voznyak 《Plasma Physics Reports》2003,29(8):657-663
Results are presented from experimental studies of the parameters of two counterpropagating (colliding) plasma flows generated
by discharges in crossed electric and magnetic fields. It is shown that the conversion efficiency of the energy deposited
in the discharges into the energy of directed plasma flows is 0.3–0.6. For discharge current pulses with a duration of ∼10
μs, the energy flux density in the plasma flow reaches ∼10 J/cm2 and the total energy of the flow is on the order of 300 J. The density of deuterons in the flows is ∼1015 cm−3, and the flow velocity is ≤2×107 cm/s. The total number of particles carried by the flows is about 1019. The possibility of using counterpropagating plasma flows to study reactions involving light nuclei (dd, pd, dt, and dHe reactions) in the range of ultralow collision energies is discussed.
__________
Translated from Fizika Plazmy, Vol. 29, No. 8, 2003, pp. 714–721.
Original Russian Text Copyright ? 2003 by Dudkin, Nechaev, Padalko, Bystritsky, Stolupin, Bystritskii, Voznyak. 相似文献
14.
A. É. Bugrov I. N. Burdonskii V. V. Gavrilov A. Yu. Gol’tsov O. L. Dedova E. V. Zhuzhukalo N. G. Koval’skii V. N. Kondrashov M. I. Pergament V. M. Petryakov I. K. Fasakhov G. M. Yankovskii 《Plasma Physics Reports》2004,30(2):143-148
New experimental data on the laser irradiation of low-density porous materials in the Mishen facility are presented and discussed. A wide set of optical and X-ray diagnostics was used to analyze the physical processes in porous media with different microstructures and specific densities of 1–30 mg/cm3 exposed to laser pulses with λ=1.054 µm, τ=3 ns, and I=1013–1014 W/cm2. The features of laser absorption and scattering and the processes of energy transfer in porous media were investigated for different average densities, thicknesses, and microstructures of the targets and different incidence angles of the laser beam. It was found that the material microstructure (chaotic or quasi-ordered) significantly affected the formation and dynamics of a plasma produced inside the irradiated samples that model the components of the advanced targets used in inertial confinement fusion research. 相似文献
15.
Extended Light Harvesting with Dual Cu2O‐Based Photocathodes for High Efficiency Water Splitting
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Wenzhe Niu Thomas Moehl Wei Cui René Wick‐Joliat Liping Zhu S. David Tilley 《Liver Transplantation》2018,8(10)
Cu2O is one of the most promising light absorbing materials for solar energy conversion. Previous studies with Cu2O for water splitting usually deliver high photocurrent or high photovoltage, but not both. Here, a Cu2O/Ga2O3/TiO2/RuOx photocathode that benefits from a high quality thermally oxidized Cu2O layer and good band alignment of the Ga2O3 buffer layer is reported, yielding a photocurrent of 6 mA cm?2 at 0 V versus reversible hydrogen electrode (RHE), an onset potential of 0.9 V versus RHE, and 3.5 mA cm?2 at 0.5 V versus RHE. The quantum efficiency spectrum (incident photon to current efficiency, IPCE) reveals a dramatically improved green/red response and a decreased blue response compared with electrodeposited Cu2O films. Light intensity dependence and photocurrent transient studies enable the identification of the limitations in the performance. Due to the complementary IPCE curves of thermally oxidized and electrodeposited Cu2O photocathodes, a dual photocathode is fabricated to maximize the absorption over the entire range of above band gap radiation. Photocurrents of 7 mA cm?2 at 0 V versus RHE are obtained in the dual photocathodes, with an onset potential of 0.9 V versus RHE and a thermodynamically based energy conversion efficiency of 1.9%. 相似文献
16.
V. P. Zimakov V. A. Kuznetsov N. G. Solovyov A. N. Shemyakin A. O. Shilov M. Yu. Yakimov 《Plasma Physics Reports》2016,42(1):68-73
The interaction of 1.07-μm laser radiation with plasma of a continuous optical discharge (COD) in xenon and argon at a pressure of p = 3–25 bar and temperature of T = 15 kK has been studied. The threshold power required to sustain COD is found to decrease with increasing gas pressure to P t < 30 W in xenon at p > 20 bar and to P t < 350 W in argon at p > 15 bar. This effect is explained by an increase in the coefficient of laser radiation absorption to 20?25 cm–1 in Xe and 1?2 cm–1 in Ar due to electronic transitions between the broadened excited atomic levels. The COD characteristics also depend on the laser beam refraction in plasma. This effect can be partially compensated by a tighter focusing of the laser beam. COD is applied as a broadband light source with a high spectral brightness. 相似文献
17.
Translational diffusion in the plasma membrane of individual egg cells from the sea urchin species Paracentrotus lividus has been studied by fluorescence microphotolysis (FM). In order to probe the lipid phase of the membrane, procedures have been worked out by which the fluorescent analog 3,3′-dioctadecyl-oxatricarbocyanine (C18diO) can be incorporated into the membrane. In the unfertilized egg a fraction R = 0.9 of C18diO was mobile having an apparent diffusion coefficient of D = 6.0 × 10?9 cm2 sec?1. Fifteen to twenty-five minutes after fertilization R and D were reduced to 0.8 and 2.7 × 10?9 cm2 sec?1, respectively. In order to study diffusion of membrane proteins, procedures have been worked out by which the cell surface can be labeled with fluorescein-isothiocyanate (FITC). FITC binds to both the plasma membrane and the vitelline layer. Together with the vitelline layer two-thirds of the FITC-fluorescence could be removed from the egg surface. Gel electropherograms of isolated egg cortices showed various protein bands; however, only two of the protein bands were labeled with FITC. In the unfertilized egg a fraction R = 0.9 of the FITC-labeled membrane proteins was mobile having an apparent diffusion coefficient of D = 35 × 10?11 cm2 sem?1. Fiteen to twenty-five minutes after fertilization R and D were reduced to 0.8 and 7.0 × 10?11 cm2 sec?1, respectively. FITC-labeled proteins of the fertilization envelope were immobile. Our studies have shown (i) that the egg surface can be fluorescently labeled without blocking fertilization and early development, (ii) that the plasma membrane of unfertilized eggs is a fluid environment permitting a rapid movement of lipids and proteins, and (iii) that after fertilization a substantial degree of lipid and protein mobility is maintained. 相似文献
18.
A. V. Vodop’yanov S. V. Golubev A. G. Demekhov V. G. Zorin D. A. Mansfel’d S. V. Razin V. Yu. Trakhtengerts 《Plasma Physics Reports》2005,31(11):927-937
Results are presented from laboratory modeling of the dynamics of space cyclotron masers. A selfoscillatory mode of cyclotron instability in the nonequilibrium plasma of an ECR discharge in a magnetic mirror trap is found. The plasma comprises two electron populations: the background population with a density of N e ~ 1013–1014 cm?3 and temperature of T e ≈ 300 eV and the energetic population with a density of N e ~ 1010 cm?3 and temperature of T e ≈ 10 keV. Quasi-periodic pulsed precipitation of energetic electrons from the trap, accompanied by microwave bursts at frequencies below the electron gyrofrequency in the center of the trap, is detected. The study of the microwave plasma emission and the energetic electrons precipitated from the trap shows that the precipitation is related to the excitation of whistler-mode waves propagating nearly parallel to the trap axis. The observed instability has much in common with phenomena in space magnetic traps, such as radiation belts of magnetized planets and solar coronal loops. The experimental results demonstrate the opportunity of laboratory modeling of space cyclotron masers. The main tasks and possibilities of such modeling are discussed. 相似文献
19.
J. Horacek S. Entler P. Vondracek J. Adamek D. Sestak M. Hron R. Panek R. Dejarnac V. Weinzettl K. Kovarik G. Van Oost 《Plasma Physics Reports》2018,44(7):652-656
The COMPASS tokamak (R = 0.56 m, a = 0.2 m, BT = 1.3 T, Ip ~ 300 kA, pulse duration 0.4 s) operates in ITER-like plasma shape in H-mode with Type-I ELMs. In 2019, we plan to install into the divertor a test target based on capillary porous system filled with liquid lithium/tin. This single target will be inclined toroidally in order to be exposed to ITER-relevant surface heat flux (20 MW/m2). Based on precisely measured actual heat fluxes, our simulations predict (for 45° inclination, without accounting for the lithium vapor shielding) the surface temperature rises up to 700°C within 120 ms of the standard ELMy H-mode heat flux with ELM filaments reaching hundreds MW/m2. Significant lithium vaporization is expected. The target surface will be observed by spectroscopy, fast visible and infrared cameras. The scientific program will be focused on operational issues (redeposition of the evaporated metal, ejection of droplets, if any) as well as on the effect on the plasma physics (improvement of plasma confinement, L–H power threshold, Zeff, etc.). After 2024, a closed liquid divertor may be installed into the planned COMPASS Upgrade tokamak (R = 0.84 m, a = 0.3 m, BT = 5 T, Ip = 2 MA, Pin = 8 MW, pulse duration ~2 s) with ITER-relevant heat fluxes loading the entire toroidal divertor. 相似文献
20.
G. M. Batanov V. D. Borzosekov L. V. Kolik E. M. Konchekov D. V. Malakhov A. E. Petrov K. A. Sarksyan A. S. Sakharov N. N. Skvortsova V. D. Stepakhin M. A. Tereshchenko N. K. Kharchev 《Plasma Physics Reports》2014,40(10):769-780
Reflection of the heating extraordinary microwave incident obliquely onto the surface of the electron cyclotron resonance (ECR) at the second harmonic of the electron gyrofrequency in the 3D magnetic configuration of the L-2M stellarator was studied experimentally. The plasma was heated using two gyrotrons with a total power of 600–700 kW, the specific heating power being 2.4–2.8 MW/m3. The displacement of the ECR region in the course of heating was monitored by measuring the phase of the reflected extraordinary wave. It is found that the growth of the plasma density is accompanied by the displacement of the ECR heating region from the center of the plasma column toward its periphery. The coefficient of reflection of the heating microwave beam from the ECR region was measured. The spectra of short-wavelength (k s ≈ 30 cm?1) plasma density fluctuations were explored by analyzing backscattered microwave radiation. A tenfold increase in the energy of short-wavelength density fluctuations and the growth of the spectral density of fluctuations in the frequency range of 0.3–1.5 MHz were observed. 相似文献