Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Atomic data (2)
- Electron diffraction (2)
- AMPTE/IRM satellite (1)
- Appearance probability (1)
- Camera systems (1)
-
- Drift distance (1)
- Electric fields (1)
- Electric space charge (1)
- Electromagnetic wave (1)
- Electromagnetism (1)
- Electron drift (1)
- Electron energy levels (1)
- Electron pulse (1)
- Electron pulse broadening (1)
- Electron pulses (1)
- Emission (1)
- Energy spreads (1)
- Femtosecond electron pulse compression (1)
- General methods (1)
- Geomagnetic field (1)
- Growth rate (1)
- Ion cyclotron wave (1)
- Laboratory (1)
- Lambertine angular distribution (1)
- Lasers (1)
- Line: profiles (1)
- Lyman alpha (1)
- Magnetometry (1)
- Magnetopause (1)
- Magnetosphere (1)
Articles 1 - 6 of 6
Full-Text Articles in Physics
Ion Contribution To The Astrophysical Important 447.15, 587.56 And 667.82 Nm He I Spectral Lines Broadening, Vladimir Milosavljevic, Stevan Djenize
Ion Contribution To The Astrophysical Important 447.15, 587.56 And 667.82 Nm He I Spectral Lines Broadening, Vladimir Milosavljevic, Stevan Djenize
Articles
Characteristics of the astrophysical important Stark broadened 447.15 nm, 587.56 nm and 667.82 nm spectral line profiles have been measured at electron densities between 0.3 10 and 8.2 10 m and electron temperatures between 8000 and 33 000 K in plasmas created in five various discharge conditions using a linear, low-pressure, pulsed arc as an optically thin plasma source operated in a helium-nitrogen-oxygen gas mixture. On the basis of the observed asymmetry of the line profiles we have obtained their ion broadening parameters ( A) caused by influence of the ion microfield on the line broadening mechanism and also …
Location Of Pc 1–2 Waves Relative To The Magnetopause, R E. Denton, J Labelle, X Zhu
Location Of Pc 1–2 Waves Relative To The Magnetopause, R E. Denton, J Labelle, X Zhu
Dartmouth Scholarship
Spacecraft-borne and ground-based magnetome- ters frequently detect magnetospheric micropulsations in the period range 0.2–10s, termed Pc 1–2, and attributed to electromagnetic ion cyclotron waves driven by temperature anisotropy (T⊥ > T∥). Previous surveys of Pc 1 occur- rence locations have been limited to L ≤ 9. We present AMPTE/IRM observations of the distribution of Pc 1 waves out to the magnetopause, for a limited region of MLT = 10–14. The probability of wave occurrence Pwav is large (> 0.15) between L = 7–12, peaking at L = 8–10 (Pwav ∼ 0.25). When the L-value is normalized to the magnetopause position Lmp, …
Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic
Stark Shifts And Transition Probabilities In The Ne Ii Spectrum, Stevan Djenize, Vladimir Milosavljevic, Milan S. Dimitrijevic
Articles
Stark shifts (d) and transition probabilities of the spontaneous emission (Einstein's A values) of forty two singly charged neon ( ) ion spectral lines have been measured in a linear, low pressure, pulsed arc at 35 300 K electron temperature and 1.83 10 23 m -3 electron density. Transition probabilities have been obtained using the relative line intensity ratio (RLIR) method. Stark shift values have also been calculated, using the semiclassical perturbation formalism (SCPF). The measured and calculated shift values and the measured A values have been compared to the existing data taken from available data sources.
Collisional And Radiative Processes In High-Pressure Discharge Plasmas, Kurt H. Becker, Peter F. Kurunczi, Karl H. Schoenbach
Collisional And Radiative Processes In High-Pressure Discharge Plasmas, Kurt H. Becker, Peter F. Kurunczi, Karl H. Schoenbach
Bioelectrics Publications
Discharge plasmas at high pressures (up to and exceeding atmospheric pressure), where single collision conditions no longer prevail, provide a fertile environment for the experimental study of collisions and radiative processes dominated by (i) step-wise processes, i.e., the excitation of an already excited atomic/molecular state and by (ii) three-body collisions leading, for instance, to the formation of excimers. The dominance of collisional and radiative processes beyond binary collisions involving ground-state atoms and molecules in such environments allows for many interesting applications of high-pressure plasmas such as high power lasers, opening switches, novel plasma processing applications and sputtering, absorbers and reflectors …
Acceleration Element For Femtosecond Electron Pulse Compression, Bao-Liang Qian, Hani E. Elsayed-Ali
Acceleration Element For Femtosecond Electron Pulse Compression, Bao-Liang Qian, Hani E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
An acceleration element is proposed for compressing the electron pulse duration in a femtosecond photoelectron gun. The element is a compact metal cavity with curved-shaped walls. An external voltage is applied to the cavity where a special electric field forms in such a way that the slow electrons in the electron pulse front are accelerated more than the fast electrons, and consequently the electron pulse duration will be compressed. The distribution of the electric field inside the acceleration cavity is analyzed for the geometry of the cavity. The electron dynamics in this acceleration cavity is also investigated numerically. Numerical results …
Electron Pulse Broadening Due To Space Charge Effects In A Photoelectron Gun For Electron Diffraction And Streak Camera Systems, Bao-Liang Qian, Hani E. Elsayed-Ali
Electron Pulse Broadening Due To Space Charge Effects In A Photoelectron Gun For Electron Diffraction And Streak Camera Systems, Bao-Liang Qian, Hani E. Elsayed-Ali
Electrical & Computer Engineering Faculty Publications
The electron pulse broadening and energy spread, caused by space charge effects, in a photoelectron gun are studied analytically using a fluid model. The model is applicable in both the photocathode-to-mesh region and the postanode electron drift region. It is found that space charge effects in the photocathode-to-mesh region are generally unimportant even for subpicosecond pulses. However, because of the long drift distance, electron pulse broadening due to space charge effects in the drift region is usually significant and could be much larger than the initial electron pulse duration for a subpicosecond electron pulse. Space charge effects can also lead …