Stark broadening of hydrogen lines in plasmas

Lisitsa, V. S.

doi:10.1070/pu1977v020n07abeh005446

Cited by 57 publications

(37 citation statements)

References 4 publications

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“…16 Stark broadening is relatively weak for nonhydrogenic lines but can become significant ͑Ͼ0.1 nm͒ and stronger than Doppler broadening for n e ӷ 10 20 m −3 and T e Ͻ 10 eV. A vast amount of literature on the theory of the Stark broadening [17][18][19] is available but may not be comprehensible to nonexperts due to the mathematical complexity. We provide an abbreviated explanation of the Stark broadening from first principles in Sec.…”

Section: Multichannel Imaging Spectroscopy Systemmentioning

confidence: 99%

Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping

Yun

Bellan

2010

Physics of Plasmas

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Collimated magnetized plasma structures are commonly observed on galactic, stellar, and laboratory scales. The Caltech plasma gun produces magnetically driven plasma jets bearing a striking resemblance to astrophysical jets and solar coronal loops by imposing boundary conditions analogous to those plasmas. This paper presents experimental observations of gun-produced plasma jets that support a previously proposed magnetohydrodynamic ͑MHD͒ pumping model ͓P. M. Bellan, Phys. Plasmas 10, 1999 ͑2003͔͒ as a universal collimation mechanism. For any initially flared, magnetized plasma tube with a finite axial current, the model predicts ͑i͒ magnetic pumping of plasma particles from a constricted region into a bulged region and ͑ii͒ tube collimation if the flow slows down at the bulged region leading to accumulation of mass and thus concentrating the azimuthal magnetic flux frozen in the mass flow ͑i.e., increasing the pinch force͒. Time-and space-resolved spectroscopic measurements of gun-produced plasmas have confirmed the highly dynamic nature of the process leading to a collimated state, namely, ͑i͒ suprathermal Alfvénic flow ͑30-50 km/s͒, ͑ii͒ large density amplification from ϳ10 17 to ϳ10 22 m −3 in an Alfvénic time scale ͑5-10 s͒, and ͑iii͒ flow slowing down and mass accumulation at the flow front, the place where the tube collimation occurs according to high-speed camera imaging. These observations are consistent with the predictions of the MHD pumping model, and offer valuable insight into the formation mechanism of laboratory, solar, and astrophysical plasma structures.

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Section: Multichannel Imaging Spectroscopy Systemmentioning

confidence: 99%

Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping

Yun

Bellan

2010

Physics of Plasmas

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“…The Stark broadening is ∆E ≈ 2 s(s -1)(kTΓ) 2 = 0.9s(s -1)Γ 2 eV [14], where s is the principal quantum number. Then, with allowance for the distance between the energy levels equal to ∆E s, s + 1 =…”

Section: The Model Proposed: Methods Of Calculationmentioning

confidence: 99%

10.1007/s11446-008-2001-z

2010

CrossRef Listing of Deleted DOIs

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“…This is a non-adiabatic contribution -since it involves different sublevels. For hydrogenic spectral lines, under the usual assumption that the fine structure can be neglected, in addition to the non-adiabatic contribution there is also a significant adiabatic contribution -see, e.g., review [19] and book [5]. Physically, the adiabatic contribution is due to the fact that for hydrogenic spectral lines, the overwhelming majority of sublevels have permanent electric dipole moments (which is especially clear in the parabolic quantization).…”

Section: Modifications In Strongly-magnetized Plasmasmentioning

confidence: 99%

Electron Density

2017

Diagnostics of Laboratory and Astrophysical Plasmas Using Spectral Lineshapes of One-, Two-, and Three-Electron Systems

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The electron density N e is the primary plasma parameter. In laboratory and astrophysical plasmas, it varies over 20 orders of magnitude (in distinction to any other plasma parameter): from N e ∼ (10 3 -10 4 ) cm −3 in astrophysical objects called H II regions to N e ∼ (10 23 -10 24 ) cm −3 in plasmas produced by very powerful lasers. (For comparison, the electron temperature T e of these two extreme types of plasmas varies only by about three orders of magnitude: from ∼1 eV in H II regions to ∼1 keV in plasmas produced by very powerful lasers.) Obviously, there is no single universal method for measuring N e that can be applied over 20 orders of magnitude. The overwhelming majority of method for measuring N e are based on Stark broadening (SB) of various spectral lines by ion and electron microfields in plasmas.SB of spectral lines in plasmas is controlled by the electron density N e and to some extent by the electron (T e ) and ion (T i ) temperatures. Therefore, it was used for measuring the electron density in a very broad range by choosing appropriate spectral lines. The experimental determination of the electron density relies mostly on measuring the Stark width because it is typically by an order of magnitude greater than the Stark shift.Hydrogenic radiators are the most appropriate for this purpose. The overwhelming majority of the states of hydrogenic radiators 3 Diagnostics of Laboratory and Astrophysical Plasmas Using Spectral Lineshapes of One-, Two-, and Three-Electron Systems Downloaded from www.worldscientific.com by 34.215.51.103 on 05/10/18. For personal use only. Diagnostics of Laboratory and Astrophysical Plasmaspossess permanent dipole moments, thus, making these radiators more sensitive to ion and electron microfields in plasmas than non-hydrogenic radiators. The underlying theories are presented in Appendices A-E, G-I, and L. In practice, there could be competing broadening mechanisms, such as, Doppler, instrumental and Zeeman broadenings, as well as a self-absorption. Therefore, the task is to find practical methods for extracting the Stark width despite the competing broadening effects, some of which could actually exceed the SB in certain situations. These methods are the focus of the subsequent sections. Using the Intense (low-n) Lines of Hydrogenic Spectral SeriesIn hydrogen atoms and hydrogenlike ions (hereafter, hydrogenic atoms, for brevity), in spectral series, i.e., in radiative transitions between the upper states of various principal quantum number n and the fixed lower state of the principal quantum number n 0 , the most intense are the lines, corresponding to n = n 0 + 1 (α-line), n 0 + 2 (β-line), n 0 +3 (γ-line), n 0 +4 (δ-line) -in order of diminishing intensity. So, on the first glance, it seems that one should use the most intense lines, like the α-line or the β-line. However, there is a trade-off. The SB of the α-line is the smallest out of the spectral series. The SB increases along the spectral series: roughly speaking, as ∼n 2 for the ion broadening and ∼n 4 for the e...

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Stark broadening of hydrogen lines in plasmas

Cited by 57 publications

References 4 publications

Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping

Plasma tubes becoming collimated as a result of magnetohydrodynamic pumping

10.1007/s11446-008-2001-z

Electron Density

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