4,637 research outputs found
On the Statistical Relationship between CME Speed and Soft X-ray Flux and Fluence of the Associated Flare
Both observation and theory reveal a close relationship between the
kinematics of coronal mass ejections (CMEs) and the thermal energy release
traced by the related soft X-ray (SXR) emission. The major problem of empirical
studies of this relationship is the distortion of the CME speed by the
projection effect in the coronagraphic measurements. We present a re-assessment
of the statistical relationship between CME velocities and SXR parameters,
using the SOHO/LASCO catalog and GOES whole Sun observations during the period
1996 to 2008. 49 events were identified where CMEs originated near the limb, at
central meridian distances between 70 and 85, and had a
reliably identified SXR burst, the parameters of which - peak flux and fluence
- could be determined with some confidence. We find similar correlations
between the logarithms of CME speed and of SXR peak flux and fluence as several
earlier studies, with correlation coefficients of 0.48 and 0.58, respectively.
Correlations are slightly improved over an unrestricted CME sample when only
limb events are used. However, a broad scatter persists. We derive the
parameters of the CME-SXR relationship and use them to predict ICME arrival
times at Earth. We show that the CME speed inferred from SXR fluence
measurements tends to perform better than SoHO/LASCO measurements in the
prediction of ICME arrival times near 1 AU. The estimation of the CME speed
from SXR observations can therefore make a valuable contribution to space
weather predictions.Comment: Solar Physics, in pres
Creating Experiences: On the Front Lines of Customer Service
Giving excellent customer service is important to our businesses. This presentation will cover what rural customers want, how to keep existing customers, how to build connections with the ‘top dogs’, and create a referral network with mavens
POSTURAL BALANCE AND BIOMECHANICAL PROBLEMS FOR THE KNEE
The increased emphasis of jogging and running and for the special few, the marathon, has increased with exploding emphasis in the past few year. If any person wished to follow the "circuit," a 10K race (6 miles), 5 miler:, or any other combination of distances, they could take part in competition in any section of the country on a daily and weekly basis providing transportation and funds were available. By and large the runner/jogger pretty much confines their activity to the local scene, running at the track, on the streets or hike and bike trails such as are found in Austin
Exploring the capabilities of the Anti-Coincidence Shield of the INTEGRAL spectrometer to study solar flares
INTEGRAL is a hard X-ray/gamma-ray observatory for astrophysics (ESA)
covering photon energies from 15 keV to 10 MeV. It was launched in 2002 and
since then the BGO detectors of the Anti-Coincidence shield (ACS) of the SPI
spectrometer have detected many hard X-ray (HXR) bursts from the Sun, producing
lightcurves at photon energies above ~ 100 keV. The spacecraft has a highly
elliptical orbit, providing a long uninterrupted observing time (about 90% of
the orbital period) with nearly constant background due to the reduction of the
crossing time of the Earth's radiation belts. However, due to technical
constraints, INTEGRAL cannot point to the Sun and high-energy solar photons are
always detected in non-standard observation conditions. To make the data useful
for solar studies, we have undertaken a major effort to specify the observing
conditions through Monte-Carlo simulations of the response of ACS for several
selected flares. We check the performance of the model employed for the
Monte-Carlo simulations using RHESSI observations for the same sample of solar
flares. We conclude that, despite the fact that INTEGRAL was not designed to
perform solar observations, ACS is a useful instrument in solar flare research.
In particular, its relatively large effective area allows the determination of
good-quality HXR/gamma-ray lightcurves for X- and M-class solar flares and, in
some cases, probably also for C-class flares.Comment: 18 pages, 6 figures; Solar Physics 201
The past, the present, and the future of future-oriented mental time travel: Editors' introduction
This introductory chapter reviews research on future-oriented mental time travel to date (the past), provides an overview of the contents of the book (the present), and enumerates some possible research directions suggested by the latter (the future)
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