Photonuclear Fission from High Energy Electrons from Ultraintense Laser-Solid Interactions

2000 ◽  
Vol 84 (5) ◽  
pp. 903-906 ◽  
Author(s):  
T. E. Cowan ◽  
A. W. Hunt ◽  
T. W. Phillips ◽  
S. C. Wilks ◽  
M. D. Perry ◽  
...  
Keyword(s):  
High Energy ◽  
High Energy Electrons ◽  
Laser Solid Interactions

scholarly journals High energy electrons, nuclear phenomena and heating in petawatt laser-solid experiments

1999 ◽  
Vol 17 (4) ◽  
pp. 773-783 ◽  
Author(s):  
T.E. COWAN ◽  
M.D. PERRY ◽  
M.H. KEY ◽  
T.R. DITMIRE ◽  
S.P. HATCHETT ◽  
...  
Keyword(s):  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
High Energy ◽  
Preliminary Evidence ◽  
Intense Laser ◽  
Photonuclear Reactions ◽  
High Energy Electrons ◽  
Preformed Plasma ◽  
Nuclear Processes ◽  
Laser Solid Interactions

The Petawatt laser at Lawrence Livermore National Laboratory (LLNL) has opened a new regime of laser matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. In addition to ∼few MeV ponderomotive electrons produced in ultra intense laser-solid interactions, we have found a high energy component of electrons extending to ∼100 MeV apparently from relativistic selffocusing and plasma acceleration in the underdense preformed plasma. The generation of hard bremsstrahlung, photonuclear reactions, and preliminary evidence for positron-electron pair production will be discussed.

scholarly journals Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

2019 ◽  
Vol 209 ◽  
pp. 01007
Author(s):  
Francesco Nozzoli
Keyword(s):  
Electron Flux ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Precision Measurements ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Positron Flux ◽  
Rigidity Dependence ◽  
Alpha Magnetic Spectrometer

Precision measurements by AMS of the fluxes of cosmic ray positrons, electrons, antiprotons, protons as well as their rations reveal several unexpected and intriguing features. The presented measurements extend the energy range of the previous observations with much increased precision. The new results show that the behavior of positron flux at around 300 GeV is consistent with a new source that produce equal amount of high energy electrons and positrons. In addition, in the absolute rigidity range 60–500 GV, the antiproton, proton, and positron fluxes are found to have nearly identical rigidity dependence and the electron flux exhibits different rigidity dependence.

scholarly journals Polar Middle Atmospheric Responses to Medium Energy Electron (MEE) Precipitation Using Numerical Model Simulations

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 133
Author(s):  
Ji-Hee Lee ◽  
Geonhwa Jee ◽  
Young-Sil Kwak ◽  
Heejin Hwang ◽  
Annika Seppälä ◽  
...  
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Meridional Circulation ◽  
Stratospheric Ozone ◽  
High Energy ◽  
Chemical Changes ◽  
Temperature Changes ◽  
Mesospheric Temperature ◽  
High Energy Electrons ◽  
Circulation Changes

Energetic particle precipitation (EPP) is known to be an important source of chemical changes in the polar middle atmosphere in winter. Recent modeling studies further suggest that chemical changes induced by EPP can also cause dynamic changes in the middle atmosphere. In this study, we investigated the atmospheric responses to the precipitation of medium-to-high energy electrons (MEEs) over the period 2005–2013 using the Specific Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Our results show that the MEE precipitation significantly increases the amounts of NOx and HOx, resulting in mesospheric and stratospheric ozone losses by up to 60% and 25% respectively during polar winter. The MEE-induced ozone loss generally increases the temperature in the lower mesosphere but decreases the temperature in the upper mesosphere with large year-to-year variability, not only by radiative effects but also by adiabatic effects. The adiabatic effects by meridional circulation changes may be dominant for the mesospheric temperature changes. In particular, the meridional circulation changes occasionally act in opposite ways to vary the temperature in terms of height variations, especially at around the solar minimum period with low geomagnetic activity, which cancels out the temperature changes to make the average small in the polar mesosphere for the 9-year period.

The Effects of High-Energy Electrons on the Charging of Spacecraft Dielectrics

1979 ◽  
Vol 26 (6) ◽  
pp. 5101-5106 ◽  
Author(s):  
M. J. Treadaway ◽  
C. E. Mallon ◽  
T. M. Flanagan ◽  
R. Denson ◽  
E. P. Wenaas
Keyword(s):  
High Energy ◽  
High Energy Electrons

scholarly journals Ovaries of Chrysanthemum Irradiated with High-Energy Photons and High-Energy Electrons Can Regenerate Plants with Novel Traits

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1111
Author(s):  
Natalia Miler ◽  
Iwona Jedrzejczyk ◽  
Seweryn Jakubowski ◽  
Janusz Winiecki
Keyword(s):  
Total Dose ◽  
In Vitro Regeneration ◽  
High Energy ◽  
Mutation Breeding ◽  
Chrysanthemum Morifolium ◽  
Physical Factors ◽  
Strong Impact ◽  
Breeding Method ◽  
High Energy Electrons

Classical mutation breeding using physical factors is a common breeding method for ornamental crops. The aim of our study was to examine the utility of ovaries excised from irradiated inflorescences of Chrysanthemum × morifolium (Ramat.) as explants for breeding purposes. We studied the in vitro regeneration capacity of the ovaries of two chrysanthemum cultivars: ‘Profesor Jerzy’ and ‘Karolina’ preceded by irradiation with high-energy photons (total dose 5, 10 and 15 Gy) and high-energy electrons (total dose 10 Gy). Growth and inflorescence parameters of greenhouse acclimatized regenerants were recorded, and ploidy level was estimated with flow cytometry. The strong impact of genotype on regeneration efficiency was recorded—cultivar ‘Karolina’ produced only 7 viable shoots, while ‘Profesor Jerzy’ produced totally 428 shoots. With an increase of irradiation dose, the regeneration decreased, the least responsive were explants irradiated with 15 Gy high-energy photons and 10 Gy high-energy electrons. Regenerants of ‘Profesor Jerzy’ obtained from these explants possessed shorter stem and flowered later. The highest number of stable, color and shape inflorescence variations were obtained from explants treated with 10 Gy high-energy photons. Variations of inflorescences were predominantly changes of shape—from full to semi-full. New color phenotypes were dark yellow, light yellow and pinkish, among them only the dark yellow phenotype remained stable during second year cultivation. None of the regenerants were haploid. The application of ovaries irradiated within the whole inflorescence of chrysanthemum can be successfully applied in the breeding programs, provided the mother cultivar regenerate in vitro efficiently.

scholarly journals Self-Organized Nanostructures Generated on Metal Surfaces under Electron Irradiation

2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Keisuke Niwase
Keyword(s):  
High Energy ◽  
Topographic Features ◽  
Exit Surface ◽  
Self Organized ◽  
Thin Foils ◽  
High Energy Electrons ◽  
Intense Electron Beam ◽  
High Doses ◽  
20 Nm ◽  
Intense Electron

Irradiation of high-energy electrons can produce surface vacancies on the exit surface of thin foils by the sputtering of atoms. Although the sputtering randomly occurs in the area irradiated with an intense electron beam of several hundred nanometers in diameter, characteristic topographic features can appear under irradiation. This paper reviews a novel phenomenon on a self-organization of nanogrooves and nanoholes generated on the exit surface of thin metal foils irradiated with high doses of 360–1250 keV electrons. The phenomenon was discovered firstly for gold irradiated at temperatures about 100 K, which shows the formation of grooves and holes with widths between 1 and 2 nm. Irradiation along [001] produces grooves extending along [100] and [010], irradiation along [011] gives grooves along [100], whereas no clear grooves have been observed for [111] irradiations. By contrast, nanoholes, which may reach depths exceeding 20 nm, develop mainly along the beam direction. The formation of the nanostructures depends on the irradiation temperatures, exhibiting an existence of a critical temperature at about 240 K, above which the width significantly increases, and the density decreases. Nanostructures formed for silver, copper, nickel, and iron were also investigated. The self-organized process was discussed in terms of irradiation-induced effects.

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