Influence of electric field of charged spacecraft on secondary emission currents on the spacecraft surface is analyzed in terms of computation of secondary electron trajectories. Dependencies of the recollected electrons number on the electric field intensity at various distances from the emission point for standard secondary electron spectra are calculated. Criteria of the secondary electron emission suppression by the surface electric field which is applied for spacecraft charging modeling using the COULOMB-2 code are proposed. Modeling of the emitted electron trajectories in the electric field of the charged spacecraft having complex surface configuration enables to compute correction factors added to electric current balance equations (electron recollection).
- A method of analysis of beam-wave interaction in passbands and stopbands of periodic slow-wave systems (SWS), based on the use of the finite-difference equation of excitation of such systems by an electron beam, is presented. In contrast to equations of a well-known beam wave interaction theory it includes the local coupling impedance, that characterizes the interaction of electrons with the total field of two waves (forward and counter-propagating) of the slow- wave system and does not tend to infinity at cutoff frequencies. It allowed to develop a general theory of interaction of electron beams and waves in passbands and stopbands of slow-wave systems without using their equivalent circuits. A study of beam wave interaction in the folded waveguide-type SWSs has been performed. An elementary analytical calculation of electro-dynamic characteristics of such SWSs necessary to study the interaction is given. Particularities of interaction in passbands and near cutoff frequencies of periodic SWSs are considered. Amplification conditions in stopbands of such slow-wave systems are discovered. Properties of beam-wave interaction at the cutoff frequency where the folded waveguide is an analog of multi-gap open resonators used in such electron devices, as an orotron, are examined.
A method of analysis of beam-wave interaction in passbands and stopbands of periodic slow-wave systems (SWS), based on the use of the finite-difference equation of excitation of such systems by an electron beam, is presented. In contrast to equations of a well-known beam wave interaction theory it includes the local coupling impedance, that characterizes the interaction of electrons with the total field of two waves (forward and counter-propagating) of the slow- wave system and does not tend to infinity at cutoff frequencies. It allowed to develop a general theory of interaction of electron beams and waves in passbands and stopbands of slow-wave systems without using their equivalent circuits. A study of beam wave interaction in the folded waveguide-type SWSs has been performed. An elementary analytical calculation of electro-dynamic characteristics of such SWSs necessary to study the interaction is given. Specifies of interaction in passbands and near cutoff frequencies of periodic SWSs are considered. Amplification conditions in stopbands of such slow-wave systems are discovered. Properties of the beam-wave interaction at the cutoff frequency where the folded waveguide is an analog of multi-gap open resonators used in such electron devices, as an orotron, are examined.
Abstract—We have performed computer simulations and experimental studies of characteristics of a standard analog device—the heterodyne employing a printed circuit board (PCB) made from a composite dielectric with a controlled dark conductivity. Simulation results show that an increased conductivity of the PCB smaller than 2 × 10^−7 Ohm^−1 · m^−1 has almost no effect on the operating characteristics of a heterodyne operating in the frequency range of 9–37 MHz, which are in a good agreement with the experimental data. Such PCBs are expected to exclude electrostatic discharges in spacecraft electronic devices otherwise occurring in them due to their internal charging by the ambient space plasma.
Abstract—This paper develops the concept of the nanoconductivity of insulators as applied to the space technology aimed at creating discharge-free space vehicles and discusses the ways to achieve this. Feasibility analysis of advanced, next generation, discharge-free satellites widely using nanoconducting insulators in spacecraft electronics proves that such a transition is not only necessary but is also practicable. We have performed computer simulations of a multivibrator, which is a typical representative of the digital technology, using the LTspice software. As any spacecraft dielectric is a potential source of the electrostatic discharges, it is advisable to implement the nanoconductivity concept by replacing high-resistivity insulators with the nanoconducting dielectrics featuring electrical conductivity around 10^−9 Ohm^ −1m^−1.
A theory is developed which describes the processes of dust particle charging in the situation when dust particles are subjected to the action of a beam of electrons. It is shown that in this situation it is necessary to consider the electron field emission in addition to the influence of the electron beam on the dust particle. We calculate the current of the electron field emission modified by the Schottky effect and find the steady-state dust particle charge. We show that in the situation considered the electrostatic energy of the dust particle is much smaller than the electron energy in the beam.
We have reviewed the basic results in the radiation-induced conductivity and the bulk charging of polymers obtained by our group during the past 30 years, which are mostly unknown in the West. Special attention is given to a new experimental technique extensively used in our investigations based on an electron-gun technology allowing combined induced conductivity and carrier mobility measurements. Quasi-band and hopping theories of the carrier transport are critically discussed.
Wave processes occurring under the interaction of the Earth's magnetosphere with dusty plasma near the lunar surface are studied. Ion-acoustic waves are shown to be excited in some regions of the magnetosphere due to the development of a linear hydrodynamic instability. This results in the excitation of ion-acoustic turbulence in these regions. Dust-acoustic waves are demonstrated to be generated due to the development of linear kinetic instability in the entire region of magnetotail interaction with dusty plasma near the Moon. Correspondingly, dust-acoustic turbulence can be excited in the entire region of the interaction of the Earth's magnetosphere with dusty plasma near the lunar surface. We discuss magnetic reconnection processes, which are related to the development of plasma turbulence at the Moon.
This paper describes modeling of spacecraft charging dynamics which is used in COULOMB-2 code in the case of spacecraft surface complex shape. The modeling of spacecraft charging is carried out via numerically solving the system of differential equations for time variations of local electric charge on every discrete element of the spacecraft surface. The presented computation results are obtained for spacecraft charging in hot magnetosphere plasma for several spacecraft design elements in a time interval of 20–10 000 s. The results are compared with the similar ones obtained with the NASCAP-2k and MUSCAT codes, and a good consistency was found.
Abstract—There are two competing tendencies in spacecraft (SC) design and manufacturing. On the one hand, it is a never-ceasing upgrading of the SC electronics to lower energy consumption and increase its functionality, which in turn makes it more susceptible to electrostatic discharges (ESDs). On the other hand, designers constantly seek to improve electronics protection against ESDs. Spectr-R SC features on-board equipment, which is highly sensitive to possible ESDs. To exclude ESD-related failures, the following protection measures have been taken. Based on the Satellite-MIEM computer code, we developed the lumped-element model of the Spectr-R body currents and cable-affected electronic response. This model made it possible to compute SC body currents initiated by ESDs originating at various structural sites. For various cable harnesses, we measured transformation coefficients converting body currents into the amplitude of the noise voltages appearing in a cable (a patented methodology was used for this purpose). Afterward, these transformation coefficients together with the ESD-induced currents have been fed into the Satellite-MIEM software to compute noise voltages appearing in electronic input circuits, connected via these cables to the satellite exterior surface. Comparing protection efficiency of cables and electronic equipment allowed us to select suitable cable harnesses and the appropriate equipment protection to insure reliable in-flight performance of the space vehicle. From the launch in July 2011 and up to the present time, there were no failures of the Spectr-R electronics, which could be traced to ESDs.
We have investigated the radiation-induced conductivity (RIC) in Kapton-like polymers in which it increases with an accumulating dose at large dose rates and long irradiation times. Such a behavior is very useful for spacecraft applications as it allows mitigating the spacecraft charging problems. Also, we studied ordinary polymers whose RIC steadily falls after reaching an initial maximum. To interpret experimental results, we used the semi-empirical Rose–Fowler–Vaisberg model. Numerical and experimental results have been compared with published data.
Dust particles under certain conditions can acquire kinetic energy of the order of 10 eV and higher, far above the temperature of gas and temperatures of ions and electrons in the discharge. Furthermore, significant difference of mean horizontal and vertical energy is observed. Such difference can be explained by the energy transfer between degrees of freedom of a dusty plasma system. The proposed mechanism of energy transfer between vertical and horizontal motion is based on parametric resonance. A system of equations describing dust particles' motion with account of dust particle charge fluctuations and features of the discharge near-electrode layer is formulated. Molecular dynamics simulations of dust particles' system are performed. Dependences of magnitude of transferred energy and horizontal energy growth rate on system parameters are obtained.
Abstract—We have simulated an electron bulk charging of the plastic cases of electronic devices as an integral part of the spacecraft internal charging problem. The semiconductor crystal has been placed inside a spherical shell of a polymer dielectric 10^−3–10^−2 m thick having an intrinsic (dark) conductivity in the range from 10^−16 to 10^−9 Ohm ^−1 ·m^−1. The crystal itself is a parallelepiped with sharp edges and vertices which substantially reduce an electrical strength of the case polymer. To assess this effect, we studied the field enhancement at the electrode as a function of its radius of curvature by measuring the reduction of the breakdown strength of air in a similar onfiguration for electrode radii 2 × 10^−5–10−^ m.