The Stark Effect of the Higher Balmer Lines in Stars of Spectral Types a and B.

1949 ◽  
Vol 109 ◽  
pp. 452 ◽  
Author(s):  
Elsa van Dien
Keyword(s):  
Stark Effect ◽  
Balmer Lines

Stark-effect of the higher Balmer lines.

1947 ◽  
Vol 52 ◽  
pp. 159
Author(s):  
Elsa van Dien
Keyword(s):  
Stark Effect ◽  
Balmer Lines

scholarly journals The emission of light from spark discharges

1946 ◽  
Vol 186 (1005) ◽  
pp. 241-260 ◽  
Keyword(s):  
Stark Effect ◽  
Light Emission ◽  
Voltage Drop ◽  
Light Output ◽  
Electron Multiplier ◽  
Near Ultraviolet ◽  
Limited Applicability ◽  
Balmer Lines ◽  
Spark Channel ◽  
Discharge Gap

The investigation is concerned with the transitory effects occurring in spark channels, after the discharge gap has been' bridged completely by a streamer. Observations have been made for various gases, in particular for hydrogen and argon, at pressures of the order of 1 atm. The main features studied are the light emitted from the spark channel during the period of current flow, and also the after-glow which persists after the current has fallen to a negligible value. The results indicate that the after-glow in hydrogen is probably a thermal effect only, whilst in argon it is due also, indeed largely, to other causes of which the persistence of atoms in metastable states is the most likely. Two main experimental methods were employed: ( a ) a revolving mirror camera, similar in principle to those used previously by several investigators, and ( b ) a photoelectric electron multiplier tube coupled directly to a cathode ray oscillograph. The latter method, which is new in investigations of this character, enables quantitative light emission results to be obtained, and methods of calibrating the apparatus are described in detail. The overall time constant of the circuit was sufficiently small to enable after-glows of duration as low as 1 μsec. to be clearly distinguished. The measurements show that for currents of about 100 amp., lasting for 2-4/isec., the after-glow in argon at a pressure of about 1 atm. could be detected after some 30 μsec., whereas in hydrogen, for similar conditions, the after-glow lasted for only some 3 μsec. Other gases showed after-glows of durations varying between the limits set by hydrogen and argon. In order to correlate the light output with energy dissipation in the spark channel, calorimetric measurements were made from which the mean voltage drop during the passage of current was estimated. The channel radii were measured with photographic plates sensitive to the visible and near ultraviolet light. Observations were also made of the spectra of the light emitted from the channel. The argon spectrum showed a strong continuum, and, for hydrogen, only the Balmer lines, much broadened, were seen. The density of ionization in the spark channels is deduced approximately in several ways, from the Stark effect, in hydrogen, and from a consideration of the energy balance in the channel, in both hydrogen and argon. The various calculations are in fairly close agreement and give N i ~10 17 ions per c.c. Channel temperatures, as determined on the basis of Saha’s equation, the limited applicability of which is discussed, are shown to be about 10,000- 15,000° K. The mechanism of light emission from the channel is discussed in some detail, and it is shown that either normal excitation or electron-ion recombination could be entirely responsible for the observed effects.

scholarly journals Time Ordering Effects on Hydrogen Zeeman-Stark Line Profiles in Low-Density Magnetized Plasmas

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
J. Rosato ◽  
D. Boland ◽  
M. Difallah ◽  
Y. Marandet ◽  
R. Stamm
Keyword(s):  
Stark Effect ◽  
Principal Quantum Number ◽  
Zeeman Effect ◽  
Magnetized Plasmas ◽  
Low Density ◽  
Stark Broadening ◽  
Simulation Code ◽  
Quantum Numbers ◽  
Balmer Lines ◽  
Hydrogen Lines

Stark broadening of hydrogen lines is investigated in low-density magnetized plasmas, at typical conditions of magnetic fusion experiments. The role of time ordering is assessed numerically, by using a simulation code accounting for the evolution of the microscopic electric field generated by the charged particles moving at the vicinity of the atom. The Zeeman effect due to the magnetic field is also retained. Lyman lines with a low principal quantum number n are first investigated, for an application to opacity calculations; next Balmer lines with successively low and high principal quantum numbers are considered for diagnostic purposes. It is shown that neglecting time ordering results in a dramatic underestimation of the Stark effect on the low-n lines. Another conclusion is that time ordering becomes negligible only when ion dynamics effects vanish, as shown in the case of high-n lines.

Calculations and Measurements of the Dynamic Stark Effect in Hydrogen

1975 ◽  
Vol 30 (6-7) ◽  
pp. 739-749 ◽  
Author(s):  
W. R. Rutgers ◽  
H. W. Kalfsbeek
Keyword(s):  
Electric Fields ◽  
Stark Effect ◽  
Neutral Atom ◽  
Low Frequency ◽  
Balmer Line ◽  
Acoustic Oscillations ◽  
Dynamic Stark Effect ◽  
Balmer Lines ◽  
Turbulent Heating ◽  
Turbulent Wave

Abstract A theory is given for the spectral profile of the first hydrogen Balmer line when the radiating neutral atom is under influence of both (quasi-) static and harmonically oscillating electric fields. Profiles, measured in a turbulent heating experiment, show a series of intensity maxima on the wings of the Balmer lines. If we assume a model for the spatial distribution of turbulent wave vectors, we can derive the fieldstrength and the direction of low-frequency (ion-acoustic) oscillations and the strength and frequency of high-frequency (Langmuir) oscillations.

The Dynamic Stark-Effect in a Turbulent Hydrogen Plasma

1974 ◽  
Vol 29 (1) ◽  
pp. 42-44 ◽  
Author(s):  
W. R. Rutgers ◽  
H. de Kluiver
Keyword(s):  
High Frequency ◽  
Stark Effect ◽  
Hydrogen Plasma ◽  
Low Frequency ◽  
Line Position ◽  
High Frequency Oscillations ◽  
Low Frequency Oscillations ◽  
Dynamic Stark Effect ◽  
Balmer Lines ◽  
Turbulent Heating

The profiles of the first three Balmer lines of hydrogen are measured in a turbulent heating experiment. From the position of Stark satellites the field strength of low frequency oscillations (ω ~ ωpi) is calculated. The energy density in these electrostatic oscillations can amount to 1% of the therm al energy. The presence of high frequency oscillations (ω ~ ωpe) is concluded from satellites near ± ωpe from the unperturbed line position.

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

A TEM study of electron tunneling in biological macromolecules

1987 ◽  
Vol 45 ◽  
pp. 140-141
Author(s):  
J. A. Panitz
Keyword(s):  
Stark Effect ◽  
Electron Tunneling ◽  
Imaging Modality ◽  
Tunneling Current ◽  
Biological Species ◽  
Scanning Tunneling ◽  
Biological Macromolecules ◽  
Flat Surfaces ◽  
Virus Particles ◽  
Stm Images

Tunneling is a ubiquitous phenomenon. Alpha particle disintegration, the Stark effect, superconductivity in thin films, field-emission, and field-ionization are examples of electron tunneling phenomena. In the scanning tunneling microscope (STM) electron tunneling is used as an imaging modality. STM images of flat surfaces show structure at the atomic level. However, STM images of large biological species deposited onto flat surfaces are disappointing. For example, unstained virus particles imaged in the STM do not resemble their TEM counterparts.It is not clear how an STM image of a biological species is formed. Most biological species are large compared to the nominal electrode separation of ∼ 1nm that is required for electron tunneling. To form an image of a biological species, the tunneling electrodes must be separated by a distance that would normally be too large for a tunneling current to be observed.

A. C. Stark effect on the 4713 Å line emitted by a helium glow discharge in the field of a multimode T.E.A. CO2 laser

1982 ◽  
Vol 43 (6) ◽  
pp. 875-881 ◽  
Author(s):  
B. Dubreuil ◽  
P. Pignolet ◽  
A. Catherinot ◽  
P. Davy
Keyword(s):  
Glow Discharge ◽  
Co2 Laser ◽  
Stark Effect

STARK EFFECT IN QUANTUM WELLS : RAMAN SCATTERING BY INTERSUBBAND TRANSITIONS

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-179-C5-182
Author(s):  
K. BAJEMA ◽  
R. MERLIN ◽  
F.-Y. JUANG ◽  
S.-C. HONG ◽  
J. SINGH ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Quantum Wells ◽  
Stark Effect ◽  
Intersubband Transitions
Sign in / Sign up

Export Citation Format

Share Document