Laboratory modeling of the high-energy particle induced ion/molecule processes in planetary atmospheres.

The atmospheres of planets in the Solar system have been explored by several space missions, including the most recent ones, Juno (Jupiter), MAVEN (Mars), and Cassini-Huygens (Titan). The atmospheres interact with energetic particles of solar wind and magnetospheric plasmas that deposit energy and drive ionospheric chemistry. The scientific instruments aboard these space probes have provided extensive data sets, which are currently being interpreted by terrestrial laboratories. The proposed project aims to investigate ion/molecule reactions induced by high-energy ions in planetary atmospheres in laboratory conditions. Sequences of ion/molecule reactions will be studied using a new ion-trap experiment. The ionic products will be described for gaseous reactant mixtures mimicking the compositions and pressures of the planetary atmosphere. This experiment will serve as proof of concept for the GACR proposal, which focuses on investigating ion/molecule reactions at cryogenic temperatures to simulate conditions found in planetary atmospheres. The new radiofrequency quadrupole ion trap can catch and store ionic products of the ion/molecule reactions in an electrostatic potential well. Combining the trap with a custom-made valve for precise gas dozing will also allow studies of consecutive ion-molecule reactions, thus faithfully modelling the atmospheric ion chemistry. The advantage of this original approach is that the produced ions can be stored for a defined time. Therefore, reaction rates of primary and secondary reaction sequences can be determined. The observation of relatively heavy ion products, with masses up to 1000 u, in these laboratory experiments could elucidate the composition of the previously enigmatic groups of high-molecular-weight positive and negative ions detected by the Cassini Plasma Spectrometer (CAPS). Structures of these ions will be characterized by collision-induced dissociation (CID) performed in the same trap (so-called MSn analysis). The requested funds will be allocated to construct the ion trap section of a magnetic sector mass spectrometer (ZAB2-SEQ) that produces mass-selected high-energy ions. Building the trap section for 100000 Kč is challenging. To stay within budget, we will reuse spare components we have in stock. We dispose of the spare linear quadrupole ion trap and different vacuum hardware which can be used. The magnetic sector mass spectrometer already has a vacuum chamber that is suitable for the trap. Part of the funds will be used for the fabrication of the mechanical construction holding the trap in the chamber. Another part of the funds will be used to purchase components for the custom-made gas valve. If the consecutive GACR application is successful, the setup will need to be modified for the cryocooling option, which will require more sophisticated hardware and an appropriate budget. Currently, the applicant is not a principal investigator of other grants. The other projects in which the applicant is involved have no relation to this application, and no funds will be allocated for this application.