|Published by the STCE - this issue : 8 Feb 2019.
The Solar-Terrestrial Centre of Excellence (STCE) is a collaborative network of the Belgian Institute for Space Aeronomy, the Royal Observatory of Belgium and the Royal Meteorological Institute of Belgium.
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Solar Orbiter is an ESA mission to perform close-up, high-resolution studies of our Sun and inner heliosphere. The project is managed and financed mainly by ESA, but with strong international collaboration. Also Belgium is involved with the Extreme Ultraviolet Imager (EUI ; see this STCE press release at - http://www.stce.be/press/EUIreadyForLaunch ) which was developed by the Centre Spatial de Liège (CSL) and the Royal Observatory of Belgium (ROB), in collaboration with the Belgian industry and foreign partners. NASA is involved as well, providing the launcher and contributing instruments to the scientific payload in the context of the International Living With a Star initiative. "SolO" 's launch is currently scheduled for 2020.
Solar Orbiter will address some central questions of heliophysics: How does the Sun create and control the heliosphere? What drives the solar wind and where does the coronal magnetic field originate from? How do solar eruptions produce energetic particle radiation that fills the heliosphere?... The spacecraft will also be the first to provide close-up views of the Sun's polar regions, which are very difficult to see from Earth, providing images from latitudes higher than 25 degrees. Solar Orbiter will also be able to nearly match the Sun's rotation around its axis for several days, allowing it to almost "hover" above active regions for an extended period of time and making it possible to see solar storms building up. As such, it will also deliver data of the side of the Sun not visible from Earth. Solar Orbiter will also coordinate its scientific mission with NASA's Parker Solar Probe to maximise their combined science return (see STCE at http://www.stce.be/news/442/welcome.html and NASA at https://www.nasa.gov/content/goddard/parker-solar-probe ).
***References and additional reading***
This text was loosely based on a number of ESA articles.
- Thermal-vacuum testing: http://www.esa.int/spaceinimages/Images/2019/01/Thermal_testing_of_Solar_Orbiter
- Heat-protective measures: http://sci.esa.int/solar-orbiter/60988-solar-orbiter-receives-its-sunblock/
- Solar Orbiter overview: https://www.esa.int/Our_Activities/Space_Science/Solar_Orbiter
- SolO instruments: http://sci.esa.int/solar-orbiter/51217-instruments/
Only one active region (NOAA AR 2733) was visible, until it rotated behind the west limb on 30 January. It produced 25 B-class flares and four C-class flares, the strongest one was a C5.2 flare peaking at 06:11 UT on 30 January.
An equatorial coronal hole (with negative polarity) traversed central meridian on 26 January.
There were no Earth directed CMEs, and the proton flux stayed below background levels.
The high speed stream (HSS) associated with the negative polarity equatorial coronal hole that traversed the central meridian on January 26, affected the Earth starting from 30 January. Compressed solar wind plasma passed the L1 point, followed by a less dense, but high speed solar wind. The magnetic field reached 20nT and the solar wind speed peaked at 620 km/s.
The geomagnetic field reached active conditions from 31 January to 2 February, both locally (K=4 at Dourbes) and at planetary levels (Kp=4). In addition, the Kp reached 5 during one 3-hour period, at 21:00 UT on 31 January. The effect of the HSS started to fade late on 2 January.
Solar flare activity fluctuated between very low and low during the week.
In order to view the activity of this week in more detail, we suggest to go to the following website from which all the daily (normal and difference) movies can be accessed: http://proba2.oma.be/ssa
This page also lists the recorded flaring events.
A weekly overview movie can be found here (SWAP week 462): http://proba2.oma.be/swap/data/mpg/movies/weekly_movies/weekly_movie_2019_01_28.mp4
Details about some of this week’s events, can be found further below.
If any of the linked movies are unavailable they can be found in the P2SC movie repository here http://proba2.oma.be/swap/data/mpg/movies/
The Space Weather Briefing presented by the forecaster on duty from January 28 to February 3. It reflects in images and graphs what is written in the Solar and Geomagnetic Activity report.
The pdf-version: http://www.stce.be/briefings/20190204_SWbriefing.pdf
The automatically running presentation: http://www.stce.be/briefings/20190204_SWbriefing.ppsm
The figure shows the time evolution of the Vertical Total Electron Content (VTEC) (in red) during the last week at three locations:
a) in the northern part of Europe(N61°, 5°E)
b) above Brussels(N50.5°, 4.5°E)
c) in the southern part of Europe(N36°, 5°E)
This figure also shows (in grey) the normal ionospheric behaviour expected based on the median VTEC from the 15 previous days.
The VTEC is expressed in TECu (with TECu=10^16 electrons per square meter) and is directly related to the signal propagation delay due to the ionosphere (in figure: delay on GPS L1 frequency).
The Sun's radiation ionizes the Earth's upper atmosphere, the ionosphere, located from about 60km to 1000km above the Earth's surface.The ionization process in the ionosphere produces ions and free electrons. These electrons perturb the propagation of the GNSS (Global Navigation Satellite System) signals by inducing a so-called ionospheric delay.