Current-Driven Instabilities and Energy Dissipation Rates As a Predictive Tool for Solar Probe Plus
Résumé
We present recent observational evidence of current-driven instabilities in the terrestrial bow shock. We use an observed positive correlation between |deltaE| and |jo| to extrapolate the results to currently inaccessible regions of space (e.g., the solar corona). Magnitudes of energy dissipation per unit volume in the solar corona due to current-driven instabilities can be estimated using electric and magnetic fields values extrapolated to coronal values. The energy dissipation values estimated this way represent an upper bound on the true energy dissipation in these regions. For instance, previous studies have estimated current densities in the solar corona to range from 104 to 107 muA m-2, which correspond to extrapolated deltaE magnitudes in excess of 12,000 mV/m and thus, energy dissipation rates in excess of 108 muW m-3. These rates are six orders of magnitude higher than is necessary to explain the temperature of the corona. Similar extrapolations can be made for astrophysical phenomena such as the surface of a neutron star. The results are of particular importance for future missions like Solar Probe Plus and Solar Orbiter.