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1.
The gravitational wave (GW) emission from a set of relativistic neutron-star (NS) merger simulations is analyzed and characteristic signal features are identified. The distinct peak in the GW energy spectrum that is associated with the formation of a hypermassive merger remnant has a frequency that depends strongly on the properties of the nuclear equation of state (EOS) and on the total mass of the binary system, whereas the mass ratio and the NS spins have a weak influence. If the total mass can be determined from the inspiral chirp signal, the peak frequency of the post-merger signal is a sensitive indicator of the EOS. 相似文献
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Coalescing binary neutron stars (NS) are expected to be an important source of gravitational waves (GW) detectable by laser interferometers. We present here a simple method for determining the compactness ratio M/R of NS based on the observed deviation of the GW energy spectrum from point-mass behavior at the end of inspiral. Our method is based on the properties of quasiequilibrium binary NS sequences and does not require the computation of the full GW signal h(t). Combined with the measurement of the NS masses during inspiral, the determination of M/R will allow very strong constraints to be placed on the equation of state of dense nuclear matter. 相似文献
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Numerical simulations for the merger of binary neutron stars are performed in full general relativity incorporating both nucleonic and hyperonic finite-temperature equations of state (EOS) and neutrino cooling. It is found that even for the hyperonic EOS, a hypermassive neutron star is first formed after the merger for the typical total mass ≈2.7M(⊙), and subsequently collapses to a black hole (BH). It is shown that hyperons play a substantial role in the postmerger dynamics, torus formation around the BH, and emission of gravitational waves (GWs). In particular, the existence of hyperons is imprinted in GWs. Therefore, GW observations will provide a potential opportunity to explore the composition of neutron star matter. 相似文献
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设计了一个紧凑型L波段相对论返波振荡器(RBWO),利用Karat 2.5维全电磁粒子模拟程序研究了器件内部束-波作用的物理过程。模拟结果表明:在二极管电压700 kV、电子束流10 kA、导引磁场为1.0 T时,能实现L波段2.23 GW高功率微波输出,平均效率约为31.8%。为验证模拟结果,在高阻加速器平台上进行了初步实验:当二极管电压为703 kV、电流10.6 kA、导引磁场为0.8 T时,实验获得了峰值功率1.05 GW、频率1.61 GHz、脉宽38 ns的高功率微波输出,其功率效率为14.4%。 相似文献
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当注入功率较高时, 大间隙速调管输入腔的基频电流分布中, 除常规意义上的最佳群聚电流峰值(第一峰值电流)外, 出现了与第一峰值电流幅值相当的第二峰值电流. 结合群聚理论和粒子模拟结果, 研究和讨论了第二峰值电流产生的机理. 研究结果表明, 第二峰值电流的出现由高电压调制系数下出现的多重电子超越效应造成. 当二极管电压600 kV, 束流5 kA, 工作频率3.6 GHz 时, 利用多重超越效应可在保持最佳群聚距离基本不变的前提下, 把大间隙速调管的束流群聚深度由80%提高到92%, 群聚束流的基频功率也从2.2 GW提高到2.8 GW, 增幅约27%.
关键词:
大间隙速调管放大器
高功率注入
多重电子超越
束流群聚 相似文献
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We study the possibility of detecting oscillating patterns in the equation of state (EoS) of the dark energy using different cosmological datasets. We follow a phenomenological approach and study three different oscillating models for the EoS, one of them periodic and the other two damped (proposed here for the first time). All the models are characterized by the amplitude, the center and the frequency of oscillations. In contrast to previous works in the literature, we do not fix the frequency to a fiducial value related to the time extension of chosen datasets, but consider a discrete set of values, so to avoid arbitrariness and try to detect any possible time period in the EoS. We test the models using a recent collection of SNeIa, direct Hubble data and Gamma Ray Bursts data. Main results are: I. even if constraints on the amplitude are not too strong, we detect a trend of it versus the frequency, i.e. decreasing (and even negatives) amplitudes for higher frequencies; II. the center of oscillation (which corresponds to the present value of the EoS parameter) is very well constrained, and phantom behavior seems statistically disfavored; III. the frequency is hard to constrain, showing similar statistical validity for all the values of the discrete set chosen, but the best fit of all the considered scenarios is associated with a period which is in the redshift range depicted by our cosmological data. The “best” oscillating models are compared with ΛCDM using different dimensionally consistent and Bayesian-based information criteria; the conclusion is reached that at present, data cannot discriminate between a cosmological constant and oscillating equation of state. 相似文献
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E. M. Tot’meninov P. V. Vykhodtsev S. A. Kitsanov A. I. Klimov V. V. Rostov 《Technical Physics》2011,56(7):1009-1012
A tunable-frequency low-magnetic-field relativistic microwave oscillator is realized experimentally based on a relativistic
backward-wave tube with a modulating resonance reflector. The generated frequency is tuned mechanically by moving the oscillator
slow-wave structure relative to the reflector. At fixed parameters of the corrugations and of the electron bunch, a frequency
tuning range of about 14% measured between −3-dB (relative to the maximum peak generated microwave power) points is realized.
The maximum pulse power of 3.4 ± 0.7 GW was obtained at a carrier frequency of 3.65 GHz in a magnetic field of 0.44 T. 相似文献
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运用超辐射机理,通过粒子模拟设计了X波段超辐射相对论返波管,并在小型Tesla脉冲源平台上开展了实验研究。通过空间功率积分和直接对辐射微波时域波形的分析得到实验结果:在束压350 kV、束流4.8 kA、脉宽3.1 ns、引导磁场2.2 T条件下,产生的微波辐射功率1.4 GW,中心频率9.36 GHz,脉宽500~700 ps,辐射模式为TE11,能在重复频率100 Hz下稳定运行。功率转换效率超过80%。实验结果与粒子模拟结果比较吻合,成功实现了在短脉冲条件下产生重复频率、亚纳秒脉宽、GW级微波辐射。 相似文献
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为了实现重频脉冲功率源小型化,研制了基于快Marx发生器的紧凑型重频低阻抗脉冲功率源。采用大功率重频高压电源对Marx发生器充电,通过对充电电源和脉冲触发源的同步控制,实现对Marx发生器重频充电;Marx发生器中采用薄膜脉冲电容器、小型化气体开关、电感隔离以及SF6气体绝缘等设计,以8级紧凑Marx发生器进行验证性研究,在16 Ω阻抗负载上实现了重复频率10 Hz、脉宽150 ns、峰值电压大于400 kV连续多脉冲输出;在此基础上,设计了18级紧凑型Marx发生器,在约18 Ω阻抗负载上输出功率达到33 GW,峰值功率密度大于150 GW/m3,实现重复频率5 Hz、脉宽约160 ns、峰值电压大于600 kV的连续多脉冲输出。为了降低Marx发生器的输出阻抗,采用4台电容器并联作为Marx发生器的一级储能模块,研制了同轴紧凑Marx脉冲功率源,有效减小放电回路电感,实现12 Ω低阻抗负载近似匹配输出,前沿减小至50 ns以下,脉宽约130 ns。 相似文献
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In the present communication, we introduce a new K-prime equation of state (EoS), which can be used to understand the interior of the Earth. The newly developed EoS is found to yield similar results as given by Stacey K-prime EoS and Keane EoS, in reference to the seismological data. However, the zero pressure and infinite pressure extrapolation of higher pressure derivatives of bulk modulus are found different for different K-prime EoS. 相似文献
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We perform a systematic study of elliptic flow(v_2) in Au+Au collisions at(~SNN)~(1/2) = 5 GeV by using a microscopic transport model, JAM. The centrality, pseudorapidity, transverse momentum and beam energy dependence of v_2 for charged as well as identified hadrons are studied. We investigate the effects of both the hadronic mean-field and the softening of equation of state(EoS) on elliptic flow. The softening of the EoS is realized by imposing attractive orbits in two body scattering, which can reduce the pressure of the system. We found that the softening of the EoS leads to the enhancement of v_2, while the hadronic mean-field suppresses v_2 relative to the cascade mode. It indicates that elliptic flow at high baryon density regions is highly sensitive to the EoS and the enhancement of v_2 may probe the signature of a first-order phase transition in heavy-ion collisions at beam energies of a strong baryon stopping region. 相似文献
18.
M. Arnaud Varvella M. C. Angonin Ph. Tourrenc 《General Relativity and Gravitation》2004,36(5):983-999
This article deals with the gravitational lensing (GL) of gravitational waves (GW). We compute the increase in the number of detected GW events due to GL. First, we check that geometrical optics is valid for the GW frequency range on which Earth-based detectors are sensitive, and that this is also partially true for what concerns the future space-based interferometer LISA. To infer this result, both the diffraction parameter and a cut-off frequency are computed. Then, the variation in the number of GW signals is estimated in the general case, and applied to some lens models: point mass lens and singular isothermal sphere (SIS profile). An estimation of the magnification factor has also been done for the softened isothermal sphere and for the King profile. The results appear to be strongly model-dependent, but in all cases the increase in the number of detected GW signals is negligible. The use of time delays among images is also investigated. 相似文献
19.
根据两腔振荡器和返波管的特点研制了过模结构返波振荡器, 该器件主要由调制腔和换能腔(慢波结构)两部分组成. 调制腔既是电子束的预调制腔, 也是微波谐振反射腔, 它同换能腔形成一个过模微波谐振腔,经调制腔调制后的电子束在换能腔中实现束波能量转换. 根据加速器的电子束参数(束压为1 MV,束流为20 kA)设计了一个X波段的高功率微波器件,2.5维粒子模拟程序模拟得到微波频率为8.25 GHz,输出功率为5.70 GW. 用超导磁体作为引导磁场,单次运行输出微波功率为5.20 GW,微波频率为(8.25±0.
关键词:
两腔振荡器
返波振荡器
多波切连科夫发生器 相似文献