Transcript The Science of Solar B Transient phenomena

The Science of Solar B
Solar B will use the combination of 3 instruments in order to provide a powerful microscope on the
Sun. These are the Solar Optical Telescope (SOT), the X-ray Telescope (XRT) and the EUV
Imaging Spectrometer (EIS) which provide high temporal, spatial and velocity resolution of the Sun
from the surface right through to the outer atmosphere. The instruments have been developed with
specific goals in mind: CORONAL HEATING, TRANSIENT PHENOMENA and ENERGY TRANSFER
FROM THE PHOTOSPHERE TO THE CORONA.
Energy Transfer from the
photosphere to the corona – this
aim encompasses all of the science
goals of solar-B. We will observe the
vector magnetic field with a spatial
resolution of 175 km, along with high
resolution images of the corona, and
high resolution velocity information.
We will be able to probe the causal
relationship between dynamics in
the photosphere and coronal
phenomena.
Coronal Heating – this problem has
been around for many decades and
huge progress has been made. We
now know that the origin of this once
mysterious heating is magnetic in
origin. However we now need to
probe this further with Solar-B’s high
spatial, temporal and velocity
resolution in order to distinguish
between for example magnetic wave
heating and small scale reconnection
events. Different phenomena such as
active regions, quiet Sun and coronal
holes are all likely to have different
heating mechanisms. Solar-B
provides us with the opportunity to
determine this.
Transient phenomena – this aim covers the
wide ranges of explosive phenomena
observed on the Sun – from small scale
flaring in the quiet Sun, to large flares, to
huge ejections of material. Some of the
missions goals include determining what
triggers flares, and coronal mass ejections.
This will ultimately feed into the currently poor
space weather prediction tools.
This figure shows the variety of data that we
will be able to obtain with Solar-B – from the
visible sunspots, to the velocity field in the
magnetic field, and how the atmosphere
responds to these changes will all be
observed. Ultimately we will be able to
compare closely with the predictions of
current (and future) theories in order to have
a deeper understanding of this fundamental
process.
This figure shows observations
made by the Norikura
Observatory, Japan, which can
obtain high spatial resolution
with accurate measurements of
velocity and line width. SolarB will be able to do this
uninterrupted in space, across a
broad range of temperatures.
This will allow us to
distinguish between wave
heating and reconnection
events.
The figure above shows the first
absolute evidence that dimming
observed in the corona is directly
related to outflowing material.
This result was obtained with
SOHO-CDS. With Solar-B, our
driver has been spectral and
temporal resolution, so that we
will regularly observe the elusive
material leaving the Sun that
forms the coronal mass ejection
as seen in coronagraph data.
The figure above shows TRACE
data of the “Bastille day” flare
in 3 temperatures. The rapid
filling up of material during the
flare can be observed from the
imagers. The figure below
shows results from Yohkoh-BCS
that demonstrate that turbulence
(determined from the spectral
line widths) is apparent 10
minutes before the flare begins.
With solar-B, we will be able to
observe the changes in
turbulence and flows accurately
in a build-up to a flare. The
combination of high spectral
resolution with imaging
capability will provide us
answers that have previously
been unobtainable with current
datasets.