Main spectral features of meteors studied using a terawatt-class high-power laser

Abstract

Context. Meteor spectra are commonly interpreted using data from databases and tables. Several studies have demonstrated very sophisticated calculations of elemental compositions of meteoroid bodies based on the computation of synthetic meteor spectra or on the spectral analysis of airglow plasma containing evaporated, atomized, and ionized meteoroid matter. However, considering accuracy, reliability of computations, lack of laboratory experimental data in this field, as well as the complicated physical structure of meteor plasma, such qualitative assignment or quantitative calculations are still extensively discussed in the scientific community. Even on the laboratory level, many studies have shown the high complexity of the acquisition and interpretation of the data that are recorded with techniques of emission spectroscopy that are in fashion and philosophy similar to the spectral analysis of meteor plasma, that is, detection and quantification of the elements that are ablated from complicated multicomponent matrices. Aims. The current study is focused on the application of terawatt-class laser-induced breakdown spectroscopy (TC-LIBS) of real samples of chondritic meteorites. We recorded emission spectra with high resolution and high precision that contain spectral lines that are typical for real meteoric spectra. Experimental data were compiled in a form that is convenient for the meteoric spectra interpretation and calibration. Methods. TC-LIBS was carried out by a high-power terawatt-class laser facility, the Prague Asterix Laser System (PALS). The spectra were simultaneously recorded by an echelle high-resolution spectrograph in the UV/VIS spectral ranges and by a low-resolution spectrograph that was used for real observation of meteor spectra. We also present calculated synthetic spectra based on data from the NIST atomic spectra database. Results. We assembled etalon qualitative tables of major meteoric spectral features that can be used both for the spectral wavelength calibration of low-resolution observational instruments and for the exact interpretation of meteor spectra. The data are compared with real meteor spectra.

Interpreting neural networks trained to predict plasma temperature from optical emission spectra

“…Upon choosing as a scaling factor, the resultant signal-to-noise levels corresponded to the values recorded in. 34,67 As a final result, the following synthetic spectra were passed into ANN analyses (See Fig. 1):…”

Nitrogen Oxide Production in Laser‐Induced Breakdown Simulating Impacts on the Hadean Atmosphere

“…The PALS laser deposits significantly greater per‐pulse energy than do tabletop LIDB facilities, and generates a greater volume of hotter plasma, with measured electronic and vibrational temperatures T exc = 8000−10 000 K and T vib = 4200–6500 K. The chemically active plasma has a diameter of about 4 cm and the resulting fireball expands at a velocity on the order of 300 km s −1 (Babánková et al., 2006; Ferus, Kubelík, et al., 2019). The electron density is estimated to reach 10 17 cm −3 .…”

Reviews in astronomy and space sciences

“…The major weakness of laser experiments is a mismatch in electron densities between observed meteors and the experiments (Křivková et al, 2021). Spectroscopic (Borovička and Betlem, 1997;Kasuga et al, 2005;Jenniskens, 2007;Ferus et al, 2018;Kubelík et al, 2022) and radar data attest to electron densities 10 11 -10 15 cm -3 , while laser induced plasma usually reaches electron densities ≈10 16 -10 20 cm −3 , which fulfils the McWhirter equilibrium criterion (De Giacomo, 2011;Ferus et al, 2018;Ferus et al, 2019;Křivková et al, 2021).…”

“…Moreover, laser plasma has been used to perform ablation experiments (Ferus et al, 2018;Ferus et al, 2019;Křivková et al, 2021). For instance, in the first comprehensive work published by (Hawkes et al, 2008), it has been proposed that laboratory-based laser ablation techniques can be used to study the size of the luminous region, predict spectral features in meteors, estimate the luminous efficiency factor, and assess the role of chemically differentiated thermal ablation of meteoroids.…”