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Abstract A new plasma heating mechanism for Microwave Discharge Ion Sources (MDIS) was discovered. Unprecedented beam stability was observed during the commissioning of the Proton Source for the European Spallation Source (PS-ESS) where several thousand source configurations were tested using a custom software tool. Data analysis and plasma simulation revealed that the new behaviour is generated by a completely new plasma heating schema activated by a precise magnetic configuration peculiarity. The stability showed in this configuration, denominated High Stability Microwave Discharge Ion Source (HSMDIS), is excellent and the emittance of the produced beam is lower than produced by standard MDIS configuration. High linearity between power and beam current was observed making easier the use of the source. This new mode of operation can be easily implemented in all existing sources.

A new plasma heating mechanism for Microwave Discharge Ion Sources (MDIS) was discovered. Unprecedented beam stability was observed during the commissioning of the Proton Source for the European Spallation Source (PS-ESS) where several thousand source configurations were tested using a custom software tool. Data analysis and plasma simulation revealed that the new behaviour is generated by a completely new plasma heating schema activated by a precise magnetic configuration peculiarity. The stability showed in this configuration, denominated High Stability Microwave Discharge Ion Source (HSMDIS), is excellent and the emittance of the produced beam is lower than produced by standard MDIS configuration. High linearity between power and beam current was observed making easier the use of the source. This new mode of operation can be easily implemented in all existing sources., (© 2022. The Author(s).)

In semiarid regions is important to use native strains best adapted to these environments to optimize plant-PGPR interaction. We aimed to isolate and characterize PGPR from roots and rhizosphere of a tomato crop, as well as studying the effect of its inoculation on tomato seedlings growth. We selected four strains considering their effectiveness of fixing nitrogen, solubilizing phosphate, producing siderophores and indole acetic acid. They belong to the genera Enterobacter, Pseudomonas, Cellulosimicrobium, and Ochrobactrum. In addition, we also analyzed the ability to solubilize Ca 3 (PO 4 ) 2 , FePO 4 and AlPO 4 and the presence of one of the genes encoding the cofactor PQQ in their genome. Enterobacter 64S1 and Pseudomonas 42P4 showed the highest phosphorus solubilizing activity and presence of pqqE gene. Furthermore, in a tomato-based bioassay in speed-bed demonstrated that a sole inoculation at seedling stage with the strains increased dry weight of roots (49-88%) and shoots (39-55%), stem height (8-13%) and diameter (5-8%) and leaf area (22-31%) and were equal or even higher than fertilization treatment. Leaf nitrogen and chlorophyll levels were also increased (50-80% and 26-33%) compared to control. These results suggest that Enterobacter 64S1 and Pseudomonas 42P4 can be used as bio-inoculant in order to realize a nutrient integrated management.