Ionization of excited atomic hydrogen by fast electrons
Fast electron calculations for atomic hydrogen excited state ionization
Omidvar, K.↗
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On the 'fast electron hypothesis' for stellar flares
It is pointed out that Gurzadyan's (1988) fast-electron hypothesis for stellar flares encounters certain difficulties. The origin of the fast electrons is obscure. Negative flares and predicted ratios of X-ray to optical fluxes are not necessarily a proof of the fast-electron hypothesis. When the electrons thermalize, they will yield X-ray fluxes which are orders of magnitude too large to be consistent with observations.
Mullan, D. J.↗
Diffusion of fast electrons in stochastic magnetic fields.
Fast electron diffusion in stochastic magnetic field, obtaining diffusion coefficient as function of ratio of correlation time to Larmor period
Feix, M. R.↗
Energy degradation of fast electrons in hydrogen gas
An equation is derived for calculating the energy distribution of fast electrons in a partially ionized gas and a method is provided to solve for the electron degradation spectrum and the energy deposition in different forms (ionization, excitation, or heating). As an example, the energy degradation of fast electrons in a gas of pure hydrogen is calculated, considering excitations to the lowest 10 atomic levels. The Bethe approximation and the continuous slowing-down approximation are discussed and it is concluded that these approximations are accurate to the order of 20 percent for electrons with initial energy of greater than about keV. The method and results can be used to determine heating, excitations, and ionizations by high-energy photoelectrons or cosmic-ray particles in various astrophysical circumstances, such as the interstellar medium, supernova envelopes, and QSO emission-line clouds.
Xu, Yueming↗
Primary and afterglow emission from supercooled nitrogen excited by fast electrons
Primary and afterglow emission from supercooled nitrogen excited by fast electrons
LIGHT EMISSION↗
Energy loss of fast electrons and positrons in a plasma.
Calculation of the stopping power of a plasma for fast electrons and positrons. First the classical limit is considered where beta = v/c is much less than alpha is the fine structure constant. Then the nonrelativistic Born-approximation formulas are derived; this domain corresponds to alpha much less than beta much less than 1. Finally, the general case of relativistic electrons and positrons is treated; in the relativistic case the scattering cross sections of Moller (electron-electron) and Bhabha (positron-electron) are used in the calculation. In all three energy domains the problem is broken up into cases of small and large momentum transfers. For large q, scattering off individual plasma electrons is considered, while in the limit of very small q for the quantum-mechanical domain, excitation of quantized plasma oscillations contributes to dE/dx; in the classical limit for small q the polarizability of the plasma provides the effective cutoff. The formulas for the stopping power differ slightly from those for a heavy ion going through a plasma because there are exchange effects and the fast electrons and positrons can lose a large fraction of their energy in one scattering off a plasma electron.
Gould, R. J.↗
A fast electron gun for study of atomic decays.
A fast electron gun with subnanosecond rise and decay times and 100 mA peak beam current has been developed for delayed coincidence studies of atomic decays. The gun is fabricated from an inexpensive tetrode nuvistor, only slightly modified. The electron gun system has been successfully used in a delayed concidence study of fast decays of ionized helium.
Sutton, J. F.↗
A fast electron gun for study of atomic decays
A fast electron gun with subanosecond rise- and decay-times and 100 ma. peak beam current has been developed for delayed coincidence studies of atomic decays. The gun is fabricated from an inexpensive tetrode Nuvistor, involving only slight modification.
Sutton, J. F.↗
Primary and afterglow emission from low- temperature gaseous nitrogen excited by fast electrons.
Primary and afterglow emission decay time from low temperature gaseous nitrogen excited by fast electrons explained by possible energy transfer
AFTERGLOW↗
Excitation cross section for some of the doubly ionized states of argon, neon and krypton by fast electrons
Excitation cross section for doubly ionized states of argon, neon, and krypton by fast electrons
Koozekanani, S. H.↗
Excitation cross section for some of the doubly ionized states of argon, neon, and krypton by fast electrons.
Excitation cross section for double ionized states of Ar, Ne and Kr due to fast electron impingement on neutral atom
Koozekanani, S. H.↗
Omnidirectional inverse Compton and synchrotron radiation from cosmic distributions of fast electrons and thermal photons.
Diffuse omnidirectional inverse Compton and synchrotron X and gamma radiation from cosmic distributions of fast electrons and thermal photons
X-RAY ASTRONOMY↗
Quantitative comparisons of type 3 radio burst intensity and fast electron flux at 1 AU
The flux of fast solar electrons and the intensity of the type 111 radio emission generated by these particles were compared at one AU. Two regimes were found in the generation of type 111 radiation: one where the radio intensity is linearly proportional to the electron flux, and another, which occurs above a threshold electron flux, where the radio intensity is approximately proportional to the 2.4 power of the electron flux. This threshold appears to reflect a transition to a different emission mechanism.
Fitzenreiter, R. J.↗
Fast electrons in small solar flares
This review summarizes both the direct spacecraft observations of nonrelativistic solar electrons, and observations of the X-ray and radio emission generated by these particles at the sun and in the interplanetary medium. These observations bear on the basic astrophysical process of particle acceleration in tenuous plasmas. We find that in many small solar flares, the nearly 5-100 keV electrons accelerated during flash phase constitute the bulk of the total flare energy. Thus the basic flare mechanism in these flares essentially converts the available flare energy into fast electrons. These electrons may produce the other flare electromagnetic emissions through their interactions with the solar atmosphere. In large proton flares these electrons may provide the energy to eject material from the sun and to create a shock wave which could accelerate nuclei and electrons to much higher energies.
Lin, R. P.↗
Quantitative comparisons of type III radio burst intensity and fast electron flux at 1 AU
We compare the flux of fast solar electrons and the intensity of the type III radio emission generated by these particles at 1 AU. We find that there are two regimes in the generation of type III radiation: one where the radio intensity is linearly proportional to the electron flux, and the second regime, which occurs above a threshold electron flux, where the radio intensity is proportional to the approximately 2.4 power of the electron flux. This threshold appears to reflect a transition to a different emission mechanism.
Fitzenreiter, R. J.↗
Fast Electronic Solar Cell Tester
Microcomputer controlled system gather current and voltage data. System consists of light source, microcomputer, programable dc power supply, analog/ digital interface, and data storage display equipment. Applies series of test loads to cell via programable dc power supply to obtain I/V characteristic curve and key cell-peformance parameter. Apparatus and programming technique are applicable to devices such as batteries and sensors.
Lathrop, J. W.↗
Simplified Formulae System for Resonant Inverse Compton Scattering of a Fast Electron in an Intense Magnetic Field
We present simple analytical formulae for the emission spectrum and total power of a special kind of resonant inverse Compton scattering (RICS) of a relativistic electron in an intense magnetic field. In contrast with the available formulae system, we obtain a markedly simplified one based on the semiclassical quantum theory, which is more understandable for people who are unfamiliar with quantum electrodynamics. We show that the RICS process, under an appropriate 'accommodation condition' derived in this paper, is predominantly much more efficient than the coexistent ordinary inverse Compton scattering, and produces highly beamed high-frequency radiation with moderately good monochromaticity. Our formulae are simple to use - thus offering a lucid physical intuition for the theory - and may find wide applications in hard X-ray and gamma-ray astrophysics.
You, J. H.↗