An EUV Non-Linear Optics Based Approach to Study the Photochemical Processes of Titan’s Atmosphere. (arXiv:1910.00362v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bourgalais_J/0/1/0/all/0/1">Jérémy Bourgalais</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carrasco_N/0/1/0/all/0/1">Nathalie Carrasco</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vettier_L/0/1/0/all/0/1">Ludovic Vettier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gautier_T/0/1/0/all/0/1">Thomas Gautier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blanchet_V/0/1/0/all/0/1">Valérie Blanchet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Petit_S/0/1/0/all/0/1">Stéphane Petit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fedorov_D/0/1/0/all/0/1">Dominique Descamps. Nikita Fedorov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Delos_R/0/1/0/all/0/1">Romain Delos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gaudin_J/0/1/0/all/0/1">Jérôme Gaudin</a>
In situ exploration of the planetary atmospheres requires the development of
laboratory experiments to understand the molecular growth pathways initiated by
photochemistry in the upper layers of the atmospheres. Major species and
dominant reaction pathways are used to feed chemical network models that
reproduce the chemical and physical processes of these complex environments.
Energetic UV photons initiate very efficient chemistry by forming reactive
species in the ionospheres of planets and satellites. Here we present a
laboratory experiment based on a new photoreactor with an irradiation beam
produced by high order harmonic generation of a near infra-red femtosecond
laser. This type of EUV source is nowadays stable enough to enable long-lasting
experiments during which a plethora of individual reactions can take place. Its
high accessibility is such that chemical initial conditions can be
systematically varied to investigate the complexity of the upper atmosphere of
planets. In order to demonstrate the validity of our approach, we shone during
7 hours at 14 eV with a flux of 1010 photons sec-1 cm-2, a N2/CH4 (5%) based
gas mixture defined by a 60 {mu}m free mean-path. Such conditions are able to
mimic the photochemistry of Titan N2 upper atmosphere. The reaction products
reveal the formation of hydrocarbons and N-bearing species like dimethyldiazene
(C2H6N2), the largest compound detected in this new photoreactor. This work
represents an important step in the use of a EUV irradiated closed-cell chamber
for the generation of photochemical analogues of Titan aerosols to better
constrain the growth pathways of nitrogen incorporation into organic aerosols
in the Titan atmosphere.
In situ exploration of the planetary atmospheres requires the development of
laboratory experiments to understand the molecular growth pathways initiated by
photochemistry in the upper layers of the atmospheres. Major species and
dominant reaction pathways are used to feed chemical network models that
reproduce the chemical and physical processes of these complex environments.
Energetic UV photons initiate very efficient chemistry by forming reactive
species in the ionospheres of planets and satellites. Here we present a
laboratory experiment based on a new photoreactor with an irradiation beam
produced by high order harmonic generation of a near infra-red femtosecond
laser. This type of EUV source is nowadays stable enough to enable long-lasting
experiments during which a plethora of individual reactions can take place. Its
high accessibility is such that chemical initial conditions can be
systematically varied to investigate the complexity of the upper atmosphere of
planets. In order to demonstrate the validity of our approach, we shone during
7 hours at 14 eV with a flux of 1010 photons sec-1 cm-2, a N2/CH4 (5%) based
gas mixture defined by a 60 {mu}m free mean-path. Such conditions are able to
mimic the photochemistry of Titan N2 upper atmosphere. The reaction products
reveal the formation of hydrocarbons and N-bearing species like dimethyldiazene
(C2H6N2), the largest compound detected in this new photoreactor. This work
represents an important step in the use of a EUV irradiated closed-cell chamber
for the generation of photochemical analogues of Titan aerosols to better
constrain the growth pathways of nitrogen incorporation into organic aerosols
in the Titan atmosphere.
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