Screening effect of impurities in metals: a possible explanation of the process of cold nuclear fusion

Summary The screening length of the deuterium ion by surrounding electrons in a palladium metal lattice, as estimated using two approaches—viz. the Thomas-Fermi screening theory and the Debye screening theory for plasmas in metal—is found to be less than the interatomic separation of ordinary hydrogen molecules. This has important implications for the possibility of cold nuclear fusion at room temperature, since slight fluctuations in equilibrium conditions may drive the deuterons to fuse together. The relative magnitudes of screening length for the cold nuclear fusion regime and classical hot nuclear regimes (inertial and magnetic confinement) reveal that in the former a comparatively smaller amount of energy is needed to overcome the repulsive Coulomb barrier between two deuterium ions.     

Shift of the photoemission threshold in III–V and II–VI semiconductors

The reasons why the photoemission threshold energy of semiconductors is lower than the ionization energy of constituent atoms have been investigated. It has been indicated that the previously proposed interpretation of this phenomenon based on the inclusion of an additional intra-atomic Coulomb interaction between the valence electrons is insufficient. It has been shown that the calculation of the electronic energy structure of semiconductors, in particular, of the photoemission threshold, requires taking into account a change in the localization region of the valence electrons when a free atom is embedded into a crystal. A way of taking this change into account in the tight-binding theory has been demonstrated. Corrections to the tight-binding Hamiltonian have been found. The photoemission thresholds of III–V and II–VI semiconductors have been calculated with the inclusion of these corrections. Comparison of the results with the experimental data has been performed.     

Nuclear fusion driven by coulomb explosions of large deuterium clusters

Recent experiments on the interaction of intense, ultrafast laser pulses with large van der Waals bonded clusters have shown that these clusters can explode with substantial kinetic energy. By driving explosions in deuterium clusters with a 35 fs laser pulse, we have accelerated ions to sufficient kinetic energy to produce DD nuclear fusion. By diagnosing the fusion yield through measurements of 2.45 MeV fusion neutrons, we have found that the fusion yield from these exploding clusters varies strongly with the cluster size, consistent with acceleration of deuterons via Coulomb explosion forces.     

Phenomenological nuclear-reaction description in deuterium-saturated palladium and synthesized structure in dense deuterium gas under γ-quanta irradiation

The observed phenomena of changes of chemical compositions in previous reports [1, 2] allowed us to develop a phenomenological nuclear fusion-fission model with taking into consideration the elastic and inelastic scattering of photoprotons and photoneutrons, heating of surrounding deuterium nuclei, following d-d fusion reactions and fission of middle-mass nuclei by “hot” protons, deuterons and various-energy neutrons. Such chain processes could produce the necessary number of neutrons, “hot” deuterons for explanation of observed experimental results [1, 2]. The developed approach can be a basis for creation of deuterated nuclear fission reactors (DNFR) with high-density deuterium gas and the so-called deuterated metals. Also, this approach can be used for the study of nuclear reactions in high-density deuterium or tritium gas and deuterated metals.     

Search for neutrons from ‘cold nuclear fusion’

We have searched for neutrons from a Pd-electrode loaded with deuterium in electrolysis setups similar to those of Fleischmann and Pons [1] and Jones et al. [2]. Within the sensitivity of our neutron detection system corresponding to a neutron source strength of 5 x 10^{? 2} neutrons/s we did not find any neutrons due to ‘cold nuclear fusion’. We emphasize the necessity of using several independent neutron detectors.     

Heating of deuterium clusters by a superatomic ultra-short laser pulse

The mechanisms of heating of the electronic component of large deuterium clusters by a super-atomic ultra-short laser pulse field are considered. During pulse rise, the so-called “vacuum heating” plays the determining role. Electrons escaping from a cluster into the vacuum with a low energy return back in a time equal to the period of the laser under laser field action. The returning electrons have a higher energy (on the order of the vibrational energy in the laser radiation field), which causes cluster heating. As the laser field increases, the electronic temperature largely grows at the expense of decreasing the Coulomb potential energy of electron repulsion because of a decrease in the number of electrons. The dynamics of above-barrier cluster ionization at the leading edge of a superatomic laser pulse is calculated. The results are discussed in the light of recent experiments aimed at creating desktop sources of monoenergetic neutrons formed as a result of the fusion of deuterium nuclei in a cluster plasma.     

Interaction of intense laser pulses with hydrogen atomic clusters

The interaction between intense femtosecond laser pulses and hydrogen atomic clusters is studied by a simplified Coulomb explosion model. The dependences of average proton kinetic energy on cluster size, pulse duration, laser intensity and wavelength are studied respectively. The calculated results indicate that the irradiation of a femtosecond laser of longer wavelength on hydrogen atomic clusters may be a simple, economical way to produce highly kinetic hydrogen ions. The phenomenon suggests that the irradiation of femtosecond laser of longer wavelength on deuterium atomic clusters may be easier than that of shorter wavelength to drive nuclear fusion reactions. The product of the laser intensity and the squared laser wavelength needed to make proton energy saturated as a function of the squared cluster radius is also investigated. The proton energy distribution calculated is also shown and compared with the experimental data. Our results are in agreement with the experimental results fairly well.     

高温氘等离子体中的势垒贯穿

讨论了高温氘等离子体中的势垒贯穿问题。在现有高温氘等离子体参数下，氘核间必须历经库仑散射与隧道贯穿相结合的复合贯穿才能引发核聚变。冷核聚变与热核聚变在本质上没有区别，都需要借助隧道效应才能发生，它们之间的差异仅在于引发隧道贯穿效应的初始条件不同。因此，在冷核聚变研究中除了过热外．也应有放射性物质的释放。     

Coulomb final state interaction in identical Boson interferometry

Recently, the muonic three-body systemdtμ, has aroused considerable attention in relation to the realization of a useful muon-catalyzed fusion [1, 2]. This bound system must be solved up to 6 digits in energy to establish the muon catalyzed fusion process. We applied the ATMS method [3] and the coupled-channel method [4] to the Coulomb three-body system and obtained the detailed information on the energy levels and the wave functions of the bound states. Further we investigated the effect of the nuclear interaction on the fusion rate in the bound states [5] and developed a formalism to calculate the muon sticking to⁴He [6]. In this paper we report the results obtained in our collaborations: Figure 2 shows up our main results.     

Dynamic acceleration effects in explosions of laser-irradiated heteronuclear clusters

Intense, femtosecond irradiation of atomic and molecular clusters can initiate Coulomb explosions, generating particle energies sufficient to drive nuclear fusion. Last and Jortner have proposed, based on particle dynamics simulations, that heteronuclear clusters with a mixture of heavy and light ions will not explode by the simple, equilibrium Coulomb model but that dynamic effects can lead to a boosting of energy of the lighter ejected ions [Phys. Rev. Lett. 87, 033401 (2001)]. We present experimental confirmation of this theoretically predicted ion energy enhancement in methane clusters.     

Plasma screening within Rydberg atoms in circular states

A Rydberg atom embedded in a plasma can experience penetration by slowly moving electrons within its volume. The original pure Coulomb potential must now be replaced by a screened Coulomb potential which contains either a screening length R_s or a screening factor A = R_s ^-1 . For any given discrete energy level, there is a Critical Screening Factor (CSF) A_c beyond which the energy level disappears (by merging into the continuum). Analytical results are obtained for the classical dependence of the energy on the screening factor, for the CSF, and for the critical radius of the electron orbit for Circular Rydberg States (CRS) in this screened Rydberg atom. The results are derived for any general form of the screened Coulomb potential and are applied to the particular case of the Debye potential. We also show that CRS can temporarily exist above the ionization threshold and are therefore the classical counterparts of quantal discrete states embedded into continuum. The results are significant not only to Rydberg plasmas, but also to fusion plasmas, where Rydberg states of multi-charged hydrogen-like ions result from charge exchange with hydrogen or deuterium atoms, as well as to dusty/complex plasmas.     

特洛伊木马方法及其应用最新进展

特洛伊木马方法是实验核天体物理中一种重要的间接测量方法,特别适合极低能区带电粒子裸核反应截面测量。在介绍特洛伊木马方法基本原理的基础上,重点讨论该方法近期在核天体物理应用中的一些重要实验结果,以及对未来研究的展望。主要介绍:AGB星s-过程关键中子源反应$ ^{{\rm{13}}}{\rm{C(\alpha ,n}}{{\rm{)}}^{{\rm{16}}}}{\rm{O}}$的间接测量,AGB星氟丰度超常现象相关核反应间接测量,以及最近热点–中等以上质量恒星碳燃烧核反应间接测量结果及相关争议。     

Antiproton-catalyzed fusion

Because of the potential application to power production, it is important to investigate a wide range of possible means to achieve nuclear fusion, even those initially appearing infeasible. In antiproton-catalyzed fusion, the negative antiproton shields the repulsion between the positively charged nuclei of hydrogen isotopes, allowing a much higher level of penetration through the repulsive Coulomb barrier and greatly enhancing the fusion cross section. With their more compact wave function, the more massive antiprotons offer much more shielding than negative muons. If the antiproton could exist in the ground state with a nucleus for a sufficient time without annihilating, the fusion cross sections are so enhanced at low energies that at room temperature, values up to about 1000 barns (d + t) would be possible. Unfortunately, the cross section for antiproton annihilation with the incoming nucleus is even higher. A model giving an upper bound for the fusion to annihilation cross section ratio for all relevant energies indicates that each antiproton will catalyze no more than about one fusion. Since the energy to make one antiproton greatly exceeds the fusion energy released, this level of catalysis is far from adequate for power production.     

Solid state effects during deuterium implantation into copper and titanium

Results of neutron counting experiments during deuterium implantation into titanium and copper are reported. Models for neutron yield have been developed by taking into account different solid state effects like energy degradation of incident ions, energy dependent d-d fusion cross section and diffusion of implanted deuterium possibly influenced by surface desorption and formation of metal deuterides. The asymptotic time dependence of the neutron yield during implantation has been compared with the experimental results. Using these results, solid state processes that might occur during deuterium implantation into these metals are inferred.     

氘核与聚变中子耦合输运方法及应用

对加速器驱动中子发生器的数值模拟包括离子输运、聚变反应、中子输运等。由于核反应截面远低于带电粒子输运的库仑截面,且核反应平均自由程远大于靶厚度,直接蒙卡抽样难以抽到聚变反应。在MCNPX程序基础上,采用“强迫”聚变方法,即每个入射氘核必发生一次聚变反应,聚变反应处氘核的真实状态(位置、能量和方向)以抽样产生,并以此状态来确定聚变中子的出射状态,实现了氘核与聚变中子的耦合输运模拟计算。研究结果表明,该方法能够给出氘核输运对聚变中子能谱和角分布的影响,中子产额计算结果符合预期。     

Fusion burning waves in degenerate plasmas

The outcome of fusion burning waves in non-degenerate plasmas is limited by the strength of ion–electron Coulomb collisions and subsequent energy loss mechanisms as electron heat conduction and radiation emission. In this Letter, an analysis is presented on the degeneracy effects in the stopping power of suprathermal charged particles and in the energy transmitted from ions to electrons by Coulomb collision. Main results of this analysis is that very powerful fusion burning waves can be launched into previously compressed degenerate plasmas. This can be specially suitable for proton–boron fusion, but it also applicable to any type of fusion reaction, where ignition can be triggered by an incoming ion beam or another external source of energy deposited in a small fraction of the compressed plasma (fast ignition).     

团簇在超强超短脉冲激光场中的演化

 利用低温脉冲气阀产生氘团簇束,在SILEX-Ⅰ激光装置上开展实验,研究氘团簇在超强超短脉冲激光场中的演化过程,获得了数十keV的高能氘离子,这些氘离子的能谱分布与库仑爆炸模型计算结果一致。实验结果表明,在一定的激光功率密度条件下,团簇的平均尺度决定了释放出高能离子的能谱分布。激光辐照团簇后,通过阈上电离部分电子逃逸团簇,随着初始电离电子屏蔽作用加强,碰撞电离变成了团簇的主要电离机制。     

中低温稠密等离子体电子压强的自洽场计算

 对含温有界自洽场平均原子结构中自由电子的判据作了修改,用分波法和Fermi-Dirac统计处理自由电子。在计算电子压强时考虑了共振态和交换、库仑关联对压强的影响。计算并与实验比较了Ni、Cu的零温电子压强。以Fe、Pb为算例,展示了本模型的适用性。     

Effect of Cluster Coulomb Fields on Electron Acceleration in Laser-Cluster Interaction

Single particle simulations are used to investigate electron acceleration in the laser-cluster interaction, taking into account the Coulomb fields around individual clusters. These Coulomb fields are induced from the cluster cores with positive charge when electrons escape from the cluster cores through ponderomotive push from the laser field. These Coulomb fields enable some stripped electrons to be stochastically in phases with the laser fields so that they can gain net energy from the laser efficiently. In this heating mechanism, circularly polarized lasers, larger cluster size and higher cluster densities make the acceleration more efficient.