Science
Recent Advances in Our Understanding of the Whole Domain
Research in the past decade has produced significant improvements in understanding the physical processes within each of the Sun-Earth domains, and enabled cross-disciplinary progress in understanding the domain as a whole. Examples include:
- The launch of satellites such as Yohkoh, SOHO and UARS have resulted in unprecedented improvements in our understanding of physical processes on the Sun and in the solar wind that generate the variable solar energies impacting Earth. These new observations and models developed from them, have facilitated progress in predicting potential geospace perturbations (from helicity signatures, halo events, and backside imaging), the impact of CME driven shocks on interplanetary magnetic fields and the magnetosphere (coordinated observations with ACE, etc.), solar driven mesospheric chemistry (using Yohkoh X-rays and mesosphere NO observations, e.g., by SNOE), ozone variations attributable to solar UV radiation and energetic protons, and solar total irradiance variations possibly associated with climate change.
- The new technique of energetic neutral atom (ENA) imaging, as conducted by the IMAGE mission, together with coincident EUV remote sensing, reveals for the first time the global distribution of particles of the inner magnetosphere and plasmasphere. Simultaneous solar and heliospheric observations enable physical interpretations of the observed global variations, such as the Bastille-day (July 14, 2000) explosive event on the Sun that caused enhanced global IMAGE maps.
- The development of self-consistent, three-dimensional, time-dependent numerical models of the thermosphere-ionosphere system allow the effects of coupling from above and below, and interactions of the neutral and ionized layers to be investigated in increasing detail. Future progress requires reliable observations, such as TIMED and COSMIC will provide, to validate the models now being developed.
SOHO EIT Solar Image for the "Bastille Day" Solar Flare
On 14 July 2000, solar Active Region 9077, in the northern solar hemisphere and just west (right) of the central meridian emitted an intense X-ray flare and large CME that was recorded by SOHO and GOES-8 and -10 as beginning just after 10:00 UT. Soon after, the ACE solar wind velocity sensor values increased rapidly and, about 11:30 UT went off scale. Optical sensors on each of the solar imaging satellites (Yohkoh, SOHO, and TRACE) were bombarded by energetic, hard-spectrum protons and heavier ions. The SOHO EIT image below, from 07:00:16 UT, shows the bright active region extending across the central meridian and to the right. This image is the first frame of a video sequence made available on the SOHO website for this event. It shows the dynamic changes until peak X-ray flare emission was reached at about 10:24 UT, and the solar image begins to be obscured by the arrival of relativistic ions around 11:00 UT.
CONTACT US:
CAWSES Office, Center for Space Physics, Boston University, 725 Commonwealth Ave. Boston, MA 02215 USA;
Phone: 617/353-5990; FAX: 617/353-6463;