ABSTRACT
Bernard V. Jacksonbvjackson@ucsd.edu
Center for Astrophysics and Space Sciences, University of California, San Diego
| Title : | 1_ Different Techniques For (and Some Success In) Measurement of Bs |
| Abstract | |
| 1_ There have been many ways proposed to measure the southward component of magnetic field (Bs) in order to determine how it couples with Earth's geomagnetic field. I will highlight the three locations interplanetary fields have been viewed in attempts to predict its effect at Earth: remotely near the Sun, remotely in the interplanetary medium on the way to Earth, and in-situ near Earth. To date, although no single technique works well to provide a certain geo-effective prediction, there has been some progress in these attempts. For a solar physicist, the sure way is to provide the best fields near the solar surface, and then through the best modeling available, project these outward. With a long distance from Sun to Earth, and many interactions along the way, a heliophysicist does his best to determine these fields, or the proxies for them, as they propagate outward. A magnetospheric physicist finds many changes in Earth's magnetic field, some related to the solar wind. At the nearby L1 Lagrange point there are in-situ measurements that can tell what will happen shortly later, and with careful analysis, an eye to individual spacecraft measurement error, and uncertainty as to the effect of the amplitude of the coupling field, the southward GSM interplanetary magnetic field component can provide a reasonable relationship to some forms of geomagnetic activity. Title: 2_ Iterative 3-D MHD ENLIL Modeling Using Interplanetary Scintillation (IPS) Observations Abstract 2_ The University of California, San Diego has developed an iterative remote-sensing time-dependent three-dimensional (3-D) reconstruction technique which provides volumetric maps of density, velocity, and magnetic field. We have applied this technique in near real time for over 15 years to a kinematic model approximation that fits data from ground-based interplanetary scintillation (IPS) observations. Our modeling concept extends volumetric data from an inner boundary placed above the Alfven surface out to the inner heliosphere. We now use this technique to drive the ENLIL 3-D MHD model at its inner boundary and generate output 3-D data files that can be fit to remotely-sensed observations (in this case IPS observations), and iterated. To facilitate this process, we have developed a traceback from input 3-D MHD ENLIL volumes to yield an updated boundary in density, temperature and velocity, which also includes magnetic-field component values. Here we will show examples of this analysis using the ENLIL 3-D MHD heliospheric code. |
|
List
|
(c) 2017 KOREA ASTRONOMY AND SPACE SCIENCE INSTITUTE All right reserved 776 Daedeokdae-ro, Yuseong-Ku, Daejeon, Rep. of Korea Korea Business Registration Number : 314-82-06495 Name of Representative : Myung Gyoon Lee Tel. 042-865-2052 Fax. 042-865-3358 Email. isest2017 (at) kasi.re.kr |
|