10 research outputs found
Electron-scale measurements of magnetic reconnection in space
Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using very high time resolution measurements, NASA’s Magnetospheric Multiscale Mission (MMS) has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth’s magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy, (ii) measured the electric field and current, which together cause the dissipation of magnetic energy, and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region
A PRELIMINARY STUDY OF MIT COUPLING AT JUPITER BASED ON JUNO OBSERVATIONS AND MODELLING TOOLS
The dynamics of the Jovian magnetosphere is controlled by the complex in- terplay of the planet’s fast rotation, its solar-wind interaction and its main plasma source at the Io torus. Juno observations have amply demonstrated that the Magnetosphere-Ionosphere-Thermosphere (MIT) coupling process- es and regimes which control this interplay are significantly different from their Earth and Saturn counterparts. At the ionospheric level, these MIT cou- pling processes can be characterized by a set of key parameters which in- clude ionospheric electrodynamic parameters (conductances, currents and electric fields), exchanges of particles along field lines and auroral emissions. Knowledge of these key parameters in turn makes it possible to estimate the net deposition/extraction of momentum and energy into/out of the Jovian upper atmosphere. We will present a method combining Juno multi-instru- ment data (MAG, JADE, JEDI, UVS, JIRAM and WAVES), adequate modelling tools (the TRANSPLANET ionospheric dynamics model and a simplified set of ionospheric current closure equations) and the AMDA data handling tools to provide preliminary estimates of these key parameters and their variation along the ionospheric footprint of Juno’s magnetic field line and across the auroral ovals for three of the first perijoves of the mission. We will discuss how this synergistic use of data and models can also contribute to provide a better determination of poorly known parameters such as the vertical struc- ture of the auroral and polar Jovian neutral atmosphere
Selenium and Mercury in Native and Introduced Fish Species of Patagonian Lakes, Argentina
Individual differences in motor timing and its relation to cognitive and fine motor skills
The present study investigated the relationship between individual differences in timing movements at the level of milliseconds and performance on selected cognitive and fine motor skills. For this purpose, young adult participants (N = 100) performed a repetitive movement task paced by an auditory metronome at different rates. Psychometric measures included the digit-span and symbol search subtasks from the Wechsler battery as well as the Raven SPM. Fine motor skills were assessed with the Purdue Pegboard test. Motor timing performance was significantly related (mean r =. 3) to cognitive measures, and explained both unique and shared variance with information-processing speed of Raven's scores. No significant relations were found between motor timing measures and fine motor skills. These results show that individual differences in cognitive and motor timing performance is to some extent dependent upon shared processing not associated with individual differences in manual dexterity