Study of the charging circuit of a pulsed solid-state laser power supply: A new concept of high charging efficiency and realization

Based on physical theory, a new concept for achieving high efficiency in a solid-state laser power supply charging circuit is first introduced in this paper that is, from the fact that when an electron from a power source enters the energy storage capacitor, a potential drop would occur in this process. This potential drop is the essence of the energy loss in a charging circuit. If the potential drop is small, or even negligible, power supply with a higher efficiency can be achieved. According to this design theory, a highly efficient charging circuit can be obtained if a power source with a single continuous increased voltage slightly higher than that of the energy storage capacitor is employed. With the use of this proposed technique, a prototype of a pulsed YAG laser power supply with high charging efficiency and high voltage charging precision is implemented. The design idea and the experimental results are described and discussed in detail.     

Rectifying behavior in Coulomb blockades: charging rectifiers

We introduce examples of tunneling and diffusive, Coulomb-regulated rectifiers based on the Coulomb blockade formalism in discrete and continuum systems, respectively. Nonlinearity of the interacting dynamics profoundly enhances the inherent asymmetry of the devices by reducing the Hilbert space of accessible states. The discrete charging rectifier is structurally similar to hybrid molecular electronic rectifiers, while the continuum-charging rectifier is based on a model of ionic flow through a pore (ion channel) with an artificial branch. The devices are formally related to ratchet systems with spatial periodicity replaced by a winding number: the current.     

Ultrahigh charging of dust particles in a nonequilibrium plasma

Charging of dust particles in a plasma with the two-temperature energy distribution of electrons has been studied. It has been shown that the dust-particle potential divided by the electron temperature decreases with increasing electron temperature in the plasma with cold ions. Owing to this behavior, the potential of the dustparticle surface increases with the electron temperature more slowly than the linear function and is lower than the electron temperature (divided by the elementary charge) for T _e > 5.5 eV in hydrogen and for T _e > 240 eV in argon. The fraction of fast electrons at which these electrons begin to contribute to the charge of dust particles has been determined. It has been shown that the charge of micron particles can reach 10⁶ elementary charges. The effect of the cold and thermal field emission on the charge of dust particles has been analyzed. The possibility of obtaining ultrahigh charges (to 10⁷ elementary charges on dust particles with a radius of 50–100 μm irradiated by a 25-keV 1-mA electron beam has been demonstrated.     

Measurement of dust grain charging in a laboratory plasma

The authors present an experimental system capable of causing dust grains to interact with a plasma in a well-controlled manner and measuring the accumulated charge. Results indicate that the measured charge accumulated on 0.1 μm diameter bismuth particles agrees to the first order with simple charging models. With further refinement of the diagnostic system, it is expected that detailed comparisons can be made with existing models     

航天器内部充电效应及典型事例分析

航天器内部充电效应是由空间高能电子诱发的,通常发生在航天器内部以及表面绝缘材料深层,所产生的放电击穿及静电放电脉冲干扰较表面充电更为严重. 对内部充放电的一般规律进行了总结,并就一次典型的航天器异常事件,从异常的时空表现特征及其与高能电子环境扰动的相关性角度进行了深入分析和定量计算,得出了高能电子产生的内部充电引起的卫星异常的结论,为卫星异常诊断提供了范例.     

航天器内部充电效应及典型事例分析

航天器内部充电效应是由空间高能电子诱发的,通常发生在航天器内部以及表面绝缘材料深层,所产生的放电击穿及静电放电脉冲干扰较表面充电更为严重. 对内部充放电的一般规律进行了总结,并就一次典型的航天器异常事件,从异常的时空表现特征及其与高能电子环境扰动的相关性角度进行了深入分析和定量计算,得出了高能电子产生的内部充电引起的卫星异常的结论,为卫星异常诊断提供了范例. 关键词： 高能电子 内部充电 静电放电 空间环境     

Attosecond resolved charging of ions in a rare-gas cluster

A scheme to probe dissipative multielectron motion in time is introduced. In this context attosecond probing enables one to obtain information which is lost at later times and cannot be retrieved by conventional methods in the energy domain due to the incoherent nature of the dynamics. As a specific example we will trace the transient charging of ions in a rare-gas cluster during a strong femtosecond vacuum-ultraviolet pulse by means of delayed attosecond pulses.     

Screening of a charged dust particle within a nonlocal charging theory

We study the influence of the nonlocality of the electron energy distribution function on the dust particle charge screening in a two-component plasma of various inert gases and nitrogen at atmospheric pressure. For our analytical and numerical calculations, we have chosen the point sink model in the diffusion-drift approximation, which, in addition to the bulk production and loss of electrons and ions, also includes the heterogeneous processes of their absorption by a dust particle. We have established that the dust particle potential distribution in the problem under consideration is a superposition of three Debye exponentials with three different screening constants. The first constant practically coincides with the inverse Debye length. The second constant is determined by the inverse length travelled by the electrons and ions in the ambipolar diffusion process in the characteristic recombination time. The third constant coincides with the inverse characteristic distance of electron energy transfer through heat conduction in the characteristic time of electron energy establishment in the processes of heating by a beam of fast electrons and energy losses in elastic and inelastic collisions. We compare our numerical calculations of the screening constants with the analytical estimates obtained in the ambipolar diffusion approximation.     

Dosed charging: Application to the investigation of papers

A dosed charging–discharging method was applied to an investigation of the paper charging properties which may be important in toner transfer in electrophotographic printers and copiers. This investigation method, which is new for paper substrates, made it possible to reveal some characteristics of paper charging and discharging processes: the dependence of charge acceptance on charging intensity, which is different for coated and uncoated papers, the change in paper charging properties during charging, unconventional charge acceptance and potential decay dependence on thickness at higher relative humidity, and the role of paper polarization in the discharge of paper.     

Single-electron charging spectra: from natural to artificial atoms

We present a theoretical study of the charging spectra in natural and artificial atoms. We apply a model electrostatic potential created by a homogenously charged sphere. This model potential allows for a continuous passage from the Coulomb potential of the nucleus to parabolic confinement potential of quantum dots. We consider electron systems with N=1,…,10 electrons with the use of the Hartree–Fock method. We discuss the qualitative similarities and differences between the chemical potential spectrum of electron systems bound to nucleus and confined in quantum dots.     

Size-dependent electron chemical potential: Effect on particle charging

Electrostatic charging of particles of identical composition, but different sizes, is a poorly understood phenomenon that may be of importance in dust storms, generation of lightning, numerous technological applications involving solid particulates, and in the agglomeration of lunar dust and inter-stellar dust clouds. We show that under optical excitation, the relative magnitude of surface to volume de-excitation gives size-dependent electron and hole concentrations. The consequent differences in chemical potentials can lead to charge transfer between particles of different size. The direction of charge transfer, from large to small or vice versa, depends critically on the properties of the materials.     

Effects of single-electron charging in a tunnel structure with a metallic cluster

The effects of single-electron tunnel charging and Coulomb blockade in a cluster structure (molecular transistor) are studied theoretically with allowance for the quantization of the electronic levels in an island electrode. The electronic spectrum is calculated for small spherical and disk-shaped clusters. Under the assumption that the total energy of the system is conserved with inclusion of the contact potential difference, equations are derived for analyzing the current-voltage characteristic. Limitations associated with the Coulomb instability of a cluster and with electron relaxation are introduced into the theory. For single-electron transistors with small gold clusters, the current gap and the asymmetry in its position on the voltage axis are calculated. The current gap is shown to vary nonmonotonically with the cluster size.     

The physics of charging a hailstone freely falling in a thunderstorm cloud

Interaction between a charged watered coarse hailstone and likely charged droplets in a uniform electrostatic field is analyzed using the electrostatic methods of images. It is shown that, under certain external conditions characteristic of a thunderstorm cloud, the droplets are attracted to the likely charged hailstone. Owing to collisions with the droplets, the hailstone freely falling in a thunderstorm cloud can gather a charge large enough to initiate a corona discharge in its vicinity.     

Single-electron charging of triangular quantum dots in a ring interferometer

Small-size semiconductor ring interferometers operating in the Coulomb blockade regime have been experimentally and theoretically studied. The conductance as a function of the gate voltage exhibits narrow quasiperiodic peaks, which are further split into doublets. Based on the experimental structural data, a three-dimensional electrostatic potential, the energy spectrum, and the single-electron transport in the interferometer were modeled. The electron system can be divided into two triangular quantum dots connected by single-mode microcontacts to each other and to the reservoirs. A model of quantum dot charging in this system is proposed that explains the appearance of doublets in the conductance-gate voltage characteristics.     

Evaluation of a soft X-ray unipolar charger for charging nanoparticles

Three types of unipolar chargers (parallel multi-electrodes, single electrode, and single electrode with compact size) using the soft X-ray were constructed and their charging performance was evaluated by measuring positive, negative, and neutral fractions of size-resolved ultrafine particles (20–100 nm) with the Tandem Differential Mobility Analyzer (TDMA) technique. The unipolar charger with a single electrode and compact size showed the highest charge fraction with least particle loss probably due to lower electrostatic loss of ions among tested chargers. With positive voltage applied to electrode to remove negative ions, we found that the positively charged particles were 43, 52, 62, 69, and 75% for 20, 30, 50, 70, and 100-nm particles, respectively, and a few particles were negatively charged although their fraction increased with size (1, 2, 4, 5, and 6% for 20, 30, 50, 70, and 100-nm particles, respectively). The positive charge fractions were about three times higher than the values estimated theoretically from a bipolar charger. Also, based on comparison of current data with previously reported values using corona discharge unipolar charger, the soft X-ray charger showed better performance in terms of charging efficiency and penetration for particles (NaCl) currently tested in the particle size range of 20–100 nm.     

Dielectric sensing by charging energy modulation in a nano-granular metal

Several sensing concepts using nanostructures prepared by focused-electron-beam-induced deposition have been developed over the last years. Following work on highly miniaturized Hall sensors for magnetic sensing with soft magnetic Co, strain and force sensing based on nano-granular platinum–carbon structures (Pt(C)) was introduced. Very recently, the capability of nano-granular Pt(C) structures to detect the presence of adsorbate water layers by conductance modulations was demonstrated. For magnetic and strain sensing, the underlying physical mechanisms of the sensing effect have been analyzed in detail and are now quite well understood. This is not the case for the adsorbate layer-induced conductance modulation effect. Here, we provide a theoretical framework that allows for a semi-quantitative understanding of the observed water-sensing effect. We show how the near-interface renormalization of the Coulomb charging energy in the nano-granular metal caused by the dielectric screening of the polarizable adsorbate layer leads to a conductance modulation. The model can account for the conductance modulation observed in the water adsorbate experiments and can also be applied to understand similar effects caused by near-interface dielectric anomalies of ferroelectric thin films on top of nano-granular Pt(C). Our findings provide a pathway toward optimized nano-granular layer structures suitable for a wide range of dielectric or local potential sensing applications.     

Kinetics of the surface charging of a semiconductor during adsorption

The kinetic characteristics of the surface charging of a semiconductor during adsorption are analyzed, due allowance being made for the recharging of the biographic surface states during the adsorption process. It is shown that the form of the kinetic curves depends very substantially on the relationship between the characteristic relaxation times of the adsorption and biographic surface states.