Image analysis of expanding laser-produced lithium plasma plume in variable transverse magnetic field

Kumar, Ajai; George, Sony; Singh, Raj; Joshi, H. C.; Nampoori, V. P. N.

doi:10.1017/s0263034611000218

Cited by 23 publications

(15 citation statements)

References 23 publications

(34 reference statements)

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“…Many research groups have investigated the interaction of magnetic field with expanding plasma and observed some interesting phenomena, such as ion acceleration/ deceleration, spectral emission intensity enhancement, electron density and temperature increase, plasma plume splitting, instability and oscillating behavior and so on [13][14][15][16]. Ajai Kumar et al [17][18][19][20] investigated the effect of magnetic field on the lithium plasma plume emission. Enhancement in the emission intensity and different structures of plasma plume in the presence of magnetic field have been observed.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced breakdown spectroscopy to monitor ion cyclotron range of frequency wall cleaning Li/D co-deposition in EAST tokamak

Liu

Sun

et al. 2017

Fusion Engineering and Design

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In this paper, laser-induced breakdown spectroscopy (LIBS) under magnetic field condition has been studied in laboratory and EAST tokamak. The experimental results reveal that in helium ambient gas, the magnetic field significantly enhances the LIBS signal intensity (~ 3 times). The effect of time delay and laser fluence on the intensity of LIBS has been investigated for optimizing the signal to background ratio (S/B). The developed LIBS approach has been applied to monitor the cleaning performance of the first wall in the fusion device of EAST using the ion cyclotron range of frequency (ICRF). The experimental results demonstrate that the cleaning performance for Li/D co-deposition layer is effective under helium ambient gas. The removing rate of Li on the surface of W tile is faster than that on Mo tile in He-ICRF cleaning and the D/(D+H) ratio on Mo tile is higher by ~ 1.2 times than that on W tile. This work would indicate the feasibility of using LIBS to monitor the wall cleaning processes in EAST tokamak.

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Section: Introductionmentioning

confidence: 99%

Laser-induced breakdown spectroscopy to monitor ion cyclotron range of frequency wall cleaning Li/D co-deposition in EAST tokamak

Liu

Sun

et al. 2017

Fusion Engineering and Design

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“…It can be seen from the spectra that the intensity of the ionic lines increased significantly with B-field presence, while the changes are minimal for neutral lines. Interestingly, for transverse magnetic field case the ionic spectral line does not exhibit any significant change with both, magnetic field and ambient gas (Kumar et al, 2011a;2011b). Figures 5 and 6 show the line intensities of Sn I (563.17 nm) and Sn II (556.19 nm) with distance from the target.…”

Section: Resultsmentioning

confidence: 94%

“…Previous studies employing a LPP expanding into a transverse B field showed that conversion of the plasma thermal energy into kinetic energy, plume confinement, ion acceleration, emission enhancement, plasma instabilities, etc. (Neogi & Thareja, 1999;Rai et al, 2003;Harilal et al, 2004;2005a;2005b;Pagano & Lunney, 2010;Kumar et al, 2011a;2011b;Pandey & Thareja, 2011). A B-field is capable of providing such a control by influencing the dynamics, ionization, and optical properties of a LPP.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of a transverse B-field on the laser-blow-off plasma plume emission also has been studied in the presence of an ambient gas (Kumar et al, 2011a;2011b). Enhancement in the intensity associated with structures was observed in the temporal profile of neutrals, which was strongly dependent on the B-field intensity, distance from the target and background gas pressure.…”

Section: Introductionmentioning

confidence: 99%

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Collimation of laser-produced plasmas using axial magnetic field

Roy¹,

Harilal²,

Hassan³

et al. 2015

Laser Part. Beams

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We investigated the expansion dynamics of laser-produced plasmas expanding into an axial magnetic field. Plasmas were generated by focusing 1.064 μm Nd:YAG laser pulses onto a planar tin target in vacuum and allowed to expand into a 0.5 T magnetic field where the field lines were aligned along the plume expansion direction. Gated images employing an intensified charge-coupled device showed focusing of the plasma plume, which were also compared with results, obtained using particle-in-cell modeling methods. The estimated density and temperature of the plasma plumes employing emission spectroscopy revealed significant changes in the presence and absence of the 0.5 T magnetic field. In the presence of the field, the electron temperature is increased with distance from the target, while the density showed opposite effects.

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“…9 Structures developed in the expanding plasma were also studied by fast imaging and were attributed to atomic processes in the plasma. 10 The emission intensity from different species in the plasma was also observed to be influenced by the applied magnetic field and was attributed to magnetic confinement. 11,12 An enhancement of 2.6 in the deposition rate was obtained in the presence of a magnetic field in case of film deposition of copper.…”

Section: Introductionmentioning

confidence: 98%

Influence of magnetic field on laser-produced barium plasmas: Spectral and dynamic behaviour of neutral and ionic species

Raju¹,

Singh²,

Gopinath³

et al. 2014

Journal of Applied Physics

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The expansion dynamics and spectral behaviour of plasma produced by a Nd:YAG laser (λ = 1.064 μm, pulse width: 8 ns) from barium target and expanding in 0.45 T transverse magnetic field in vacuum (10−5 Torr pressure) are investigated using time-of-flight optical emission spectroscopy. The experiments are carried out at various laser fluences from 12 to 31 J/cm2. The temporal profiles of neutral (Ba I 553.5 and 577.7 nm) lines are temporally broadened, while that of ionic (Ba II 413.0 and 455.4 nm) lines show strong confinement in the presence of a magnetic field. In the absence of magnetic field, the temporal profile of Ba I 553.5 nm is exactly reproduced by fitting with two Shifted Maxwell Boltzmann (SMB) Distribution components, while in the presence of a magnetic field the profile could only be fitted with three components. The field enhanced and field induced SMB components of neutral profile are correlated with populations of ground state, metastable states, and long-lived Rydberg states present in the barium plasma, while SMB components of ionic lines are explained on the basis of the presence of super-elastic collisions among the excited species in the plasma. The spatial variation of electron temperature and temporal variation of electron density are deduced and correlated to the different collisional processes in the barium plasma. The ionic profiles show efficient confinement in the presence of a magnetic field at higher fluences.

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Image analysis of expanding laser-produced lithium plasma plume in variable transverse magnetic field

Cited by 23 publications

References 23 publications

Laser-induced breakdown spectroscopy to monitor ion cyclotron range of frequency wall cleaning Li/D co-deposition in EAST tokamak

Laser-induced breakdown spectroscopy to monitor ion cyclotron range of frequency wall cleaning Li/D co-deposition in EAST tokamak

Collimation of laser-produced plasmas using axial magnetic field

Influence of magnetic field on laser-produced barium plasmas: Spectral and dynamic behaviour of neutral and ionic species

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