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FOXSI: The NASA mission that combines rockets, flares, and X-rays

FOXSI: The NASA mission that combines rockets, flares, and X-rays

For decades, high-energy aspects of the Sun have been studied using indirect imaging and spectroscopy in hard X-rays (HXR) by the pioneering RHESSI spacecraft. However, advanced understanding of small-scale energy releases and particle acceleration in the outermost layer of the Sun require better sensitivity and dynamic range, which can be achieved by using direct focusing X-ray optics. Almost six years ago, in 2012, the Focusing Optics X-ray Solar Imager (FOXSI) rocket experiment first imaged the Sun in hard X-rays (4 – 20 keV) using direct focusing optics, from an altitude of about 300km. The second flight in 2014 made striking observations such as the evidence for the existence of solar nanoflares from a non-flaring active region [1] and plasma temperature distribution of microflares.

The Terrier/Black Brant IX rocket successfully launched FOXSI-3 to observe the X-ray Sun, Sep. 7, 2018 from Launch Complex 36 at White Sands Missile Range, New Mexico.

On 7 September 2018, team FOXSI launched its third successful flight from White Sands Missile Range (WSMR), New Mexico. FOXSI-3 flight also served as a test bed for advanced space instrumentation such as
(i) ‘3D printed collimator’ to block X-rays coming off the coverage area,
(ii) fine pitch CdTe strip detectors, and
(iii) Soft X-ray (SXR) capability to our telescope using CMOS sensors.

To focus X-rays, the team uses extremely polished surfaces called ‘X-ray mirrors’, fabricated and calibrated at NASA Marshall. FOXSI uses 7 optic modules, with each containing nested X-ray mirrors, coated with Iridium. Photons hitting at grazing angles (less than 0.5°) get reflected to a focal point from where they are imaged using photon counting energy sensitive semiconductor detectors made of Si and CdTe. The flight optic modules were calibrated using the Stray Light Facility at NASA Marshall. The blocking performance of 3D printed collimator and blockers were well tested and duly validated with ray tracing simulations. The HXR detectors were calibrated at the University of Minnesota, while operating at -10°C using a well tailored temperature controller that met all the requirements for a controlled cooling and warming up. Our Japanese collaborators provided the PhoEnIX (Photon Energy Imager in X-rays) instrument, which added soft X-ray capability to the FOXSI-3 experiment by observing in the 0.5 – 5 keV using CMOS sensors. The solar alignment aspect system was developed and tested at NASA Goddard.

Happy FOXSI-3 team after passing all the required tests and got a nod to go ahead for launch!

Mechanical fit checks and optics alignment tests were conducted at SSL, Berkeley before shipped to WSMR. We spent weeks of tireless teamwork and carried out all necessary checks, with proper breaks for outing and cooking! We started our launch day at 2.30AM by kicking our cooler to ramp down to -20°C, while we rejoiced yummy donuts, cookies and coffee. Watched the impressive launch, steered our telescope for ~ 6 minutes and observed the X-ray Sun!

Simultaneous imaging and spectroscopy of the Sun in SXR and HXRs using direct focusing optics and photon counting detectors have never been done before! FOXSI-3 demonstrates the technology readiness and robustness available for a future dedicated solar HXR space observatory to study the high-energy phenomena with intricate details. This will unavoidably broaden the horizons of the solar and heliospheric community. Preliminary results from FOXSI-3 will be discussed in the American Geophysical Union Fall Meeting in December 2018.

[1] Detection of nanoflare-heated plasma in the solar corona by the FOXSI-2 sounding rocket, S. Ishikawa, L. Glesener, S. Krucker, S. Christe, C. Buitrago-Casas, N. Narukage, J. Vievering, Nature Astronomy, 2017

 

 

This post is written by Subramania Athiray Panchapakesan
from the FOXSI team working in the University of Minnesota

EGU for Early Career Scientists

EGU for Early Career Scientists

Theresa Rexer

This months post is written by the ST Divisions Early Career Scientist representative, Theresa Rexer.

Are you ready for the EGU general assembly 2019? Got your abstract ready and submitted? No, what? Too early you say? No funds? As your Early Career Scientist Representative, let me tell you why now is the perfect time to start planning your trip to Vienna in April next year. Especially if you are an Early Career Scientist!

 
EGU2019 aka the best meeting for Early Career Scientist in geosciences
At the general assembly (GA) more than half the participants are actually early career scientist  which is defined as students at all stages or scientist who have finished their MSc or PhD within the past 7 years. Because of this, a large effort is made every year to make the meeting especially relevant for ECSs. There are numerous Short Courses that are specifically organised for ECSs. Want to know how others find their way around the huge conference site? Or how you can get the most out of you next poster or PICO presentations? The short courses are sessions or workshops that are complementary to the scientific talks at the GA , ranging from a host of general topics like visualising your research, how to navigate the GA or How to get your next job or research grant in academia that are relevant to all ECSs, to division specific topics where you can get an introduction to topics and technics specific to a field of research. 
In the Short course of the Solar-Terrestrial division, SC3.7/ST4.11: Meet the experts: The future of Solar terrestrial Research, you will get a unique chance to discuss the future challenges and opportunities with experienced and renown scientists in our field. You have heard of them. You might have read their papers. Now is your chance to talk to them and ask: What’s next for us
You can also meet your fellow ECSs, your future friends and colleagues, at one of the many social events like the Early career Scientists reception, the ECS forum meeting or in the ECS Lounge area, where free coffee and soft drinks are served and a series of pop-events for ECSs are held during the week. 
Still unsure and none of your colleagues are going? Consider signing up for the mentoring programme where ECSs are matched with a senior scientist to help you navigate the conference, network with other conference attendees, and exchange feedback and ideas on professional activities and your career development.
 
“So why plan now? The deadline isn’t until January…”
Did you know that, as an ECS, you can apply for travel support? If you submit your abstract by December 1st 2018, you registration fee and travel expenses for up to 300 Euro could be covered for you. All you have to do is write and submit your abstract before December 1st and apply for the Early Career Scientist Travel Support. This is a great opportunity and December is closer than you think, so don’t wait. Submit your abstract, apply for support and get ready for next years best early career scientist conference. 
 
Not an ECS? The early bird still catches the bird….or the medal! The Vienna City Marathon (also includes a half-marathon and 10k runs) is held the weekend just before the GA and tickets are sold fast. You are correct in thinking that a number of your fellow ST division scientists and ECSs are participating, so join us!
 
If you have any questions, suggestions, ideas or if you wish to join the Solar-Terresrial ECS Team, do not hesitate to contact me at ecs-st@egu.eu
 
 
See you in April!
– Theresa

The average magnetic field and polar current system (AMPS) model

The average magnetic field and polar current system (AMPS) model

Karl Magnus Laundal. Credit: BCSS

In this month’s post, Karl Magnus Laundal explains a newly developed empirical model for the full high latitude current system of the Earth’s ionosphere, AMPS (Average Magnetic field and Polar Current System). The model is available and documented in python code, published under the acronym pyAMPS. The community is invited to download and explore the electric currents and magentic field disturbances described by the model.

 

 

The average magnetic field and polar current system (AMPS) model

At about 10 times airline cruising altitude, at the boundary to space, the atmosphere is so thin that charged particles, electrons and ions, are not immediately neutralized in collisions. This inner edge of space, which extends from about 100 to 1000 km altitude, is called the ionosphere. In contrast to the neutral atmosphere, the charged particles feel the forces of electromagnetism. These forces depend strongly on the interaction between the solar wind and the Earth’s magnetic field, which happens much further out, at about 10 Earth radii (roughly twice as distant as geostationary satellites, but well inside lunar orbit). The result of this interaction is communicated to the upper atmosphere along magnetic field lines, and as a result, a 3-dimensional current system is generated in the ionosphere. This current system can change very rapidly, partly because of changes in the solar wind and in the interplanetary magnetic field.

Field aligned currents (red/blue) and divergence free horizontal currents (contours) from AMPS, during the course of a day. Credit: K.M. Laundal

The AMPS model describes the average ionospheric magnetic field and current system for a given solar wind speed, interplanetary magnetic field vector, orientation of the Earth’s magnetic dipole axis, and the value of a solar flux index (F10.7). The model is empirical, which means that it is derived from measurements. We use measurements of the magnetic field, from the CHAMP and Swarm satellites, in low Earth orbit. For each measurement, model estimates of Earth’s own magnetic field, and the magnetic field associated with large-scale magnetospheric currents, have been subtracted. The remaining magnetic field is assumed to be related to ionospheric currents. Millions of measured magnetic field vectors are used to fit several thousand unknown parameters in an intricate mathematical function that describes the ionospheric magnetic field at any point in time and space. Electric currents are calculated from the magnetic field.

Model values of AMPS magnetic fields and currents can be calculated with the Python library pyAMPS, which is located here: https://github.com/klaundal/pyAMPS (documentation here: http://pyamps.readthedocs.io/).

This is not the first empirical model of ionospheric currents and magnetic fields, but there are a couple of important characteristics that sets the AMPS model apart from others: First, we have corrected for variations in Earth’s own magnetic field, which strongly distorts the ionospheric currents. This allows us to make precise comparisons between hemispheres. We have not imposed any symmetries between hemispheres; for example seasonal variations are not necessarily the same in the north and south in the AMPS model. Finally, this is the first empirical model to describe the full ionospheric current system, and not only the field-aligned part or the parts which circulates horizontally. This allows us to calculate full horizontal ionospheric current vectors without any assumptions about conductivity.

These unique features are made possible by the dataset provided by the CHAMP and Swarm missions, of very accurate magnetic field measurements from low orbit. The CHAMP satellite reentered Earth’s atmosphere in 2010, after 10 years of operation. In 2013, ESA’s Swarm satellites were launched, three satellites that carry even more precise magnetometers than CHAMP. So far, two of the Swarm satellites have flown side-by-side, near 450 km altitude, while the third satellite is a little higher. Swarm is expected to stay in space for many years, and we plan to release updated versions of the AMPS model as the data set grows. The production and publication of the AMPS model is supported by ESA through Swarm DISC.

A paper describing the model has been published in Journal of Geophysical Research – Space Physics: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JA025387 (open access)

For more background on the technique, see an earlier paper in a special Swarm issue of Earth, Planets, and Space:
https://earth-planets-space.springeropen.com/articles/10.1186/s40623-016-0518-x (open access)

Report from the 2018 EGU General Assembly

Report from the 2018 EGU General Assembly

Last week the 2018 General Assembly were held in Vienna. Gathering 15 075 scientists from 106 countries, this is the most important EGU event throughout the year. Summarizing what happened during the week is an impossible task, as a meeting like this is way more than the 666 individual sessions convened and the 11 128 posters presented during the week. However, in this post I will point to some of the ST Division specific highlights.

This year, spring came to Vienna together with EGU. Many of us therefore used this excellent opportunity to stay outside in the sun to relax or explore the beautiful medieval city, in between the busy meeting schedule. However, the main activities happened inside the Austria Center Vienna. 

During the Solar-Terrestrial Division meeting, Theresa Rexer was announced as the new Early Career Scientist (ECS) representative in the division, taking over from Jone Peter Reistad. She will continue the ongoing efforts to make the General Assembly even more relevant for students and researchers in the early stages of their career. During the General Assembly, the Solar-Terrestrial ECS team held the session “Meet the Experts: The Future of Solar Terrestrial Research”, for the fourth year in a row. The session was very well attended (78 participants) and the invited speakers did an excellent job in reviewing important challenges and topics relevant for ECS to embark upon in the near future, covering topics from the Sun to the magnetosphere, ionosphere, and its coupling with the atmosphere.

This year we had three medal awardees in the ST division. Ilya Usoskin received on the Monday the Julius Bartels medal for his “key contributions to long-term changes of cosmic rays and solar activity, qualifying him as a founder of the space climate discipline”. The next day Eckart Marsch received the Hannes Alfvén medal for “fundamental contributions to our understanding of the kinetic processes and plasma turbulence in the heliosphere, as well as for work that helped HELIOS become a successful mission and initiated the Solar Orbiter.” Finally, Natasha L. S. Jeffrey received the Division Outstanding Early Career Scientist Award for “her outstanding achievements in improving the standard model of fast electrons produced in solar flares, thereby eliminating the long-standing low-energy cut-off uncertainty.” (citations are from https://www.egu.eu/awards-medals/).

In the Solar-Terrestrial Division, a total number of 34 session were held, making up a varied program within most of the disciplines of our division due to all the contributions and efforts from the community. I can only say that I look very much forward to the meeting in Vienna next year!

Social media response to geomagnetic activity

Social media response to geomagnetic activity

Social media platforms offer every person with internet access the possibility to share content of various kind. The recent increase in social media use globally give birth to new tools and insights, from a different perspective. The size of, and the global nature of the user driven social media, makes one expect it to include information also about geomagnetic activity related to posts of visual observations of the aurora by the users. Inspired by the ongoing Aurorasaurus initiative, an outreach project with a High School class in Norway was undertaken, where the students were given the task to see if they could find any connection between the number of social media reports of aurora (using Twitter), and the observed level of geomagnetic activity (using the AL index). Their results showed a highly significant correlation, especially during the months of high geomagnetic activity, as seen in the above plot.

We here include a short project report from one of the groups to share details on how the investigation was done. The text has been prepared by Simen Sande Bergaas, Lea Sommersten Brandstadmoen, Trym Svardal Larsen, and Ingri Østensen from Langhaugen High School, Norway, together with two of their teachers.

The students from Langhaugen High School participating in the project. Credit: Silje Rognsvåg Reistad

Introduction

We wanted to find out whether social media could be a valid source for finding out how much northern light there had been, and when it appeared. We used Twitter as our social media, and searched on one specific date, so we could see how much northern light there had been each day. We wanted to see if there were any similarities between a geomagnetic activity index (AL) and the number of hits we got on Twitter.

Method

  • Each group looked at one month between September 2016 and April 2017
  • We counted the hits on Twitter for #northernlights and/or #auroraborealis each day of our month
  • We plotted these results together with the daily average geomagnetic index (AL) using Excel.

Results

As we can see from the top figure, we got a good match between the daily Twitter count and the AL index. We got similar results for most of the eight months. The only month that we did not see any correlation was December, in which had very low Twitter counts.


How many of the Tweets were relevant?

One of the groups wanted to do something more with the project, and decided to count how many of the posts we found were relevant, and actually showed northern lights that had occurred that day. We chose one of the days, and then we counted. The result is shown in the figure below. The day we counted, there were 96 posts. Out of these 96 posts, 22 did not contain relevant information to our project. That equals 23% non-relevant posts, and 77% relevant posts.

Breakdown of all Twitter posts on March 11, 2017. Most of the posts (77%) were found to be related to auroral activity.

 

Conclusions

What we saw from these statistics was that there are similarities between the measurements and the Twitter posts. We can say that social media can be a somewhat valid source for describing the geomagnetic activity level, but not a waterproof one. Looking at the other months, it looks like the correlation improves during active times, while December, which was a quiet month, had very poor correlation. We also see that on March 11, very few of the posts were non-relevant, which strengthens the credibility of social media as a source. 

 

The students presented their work on posters to the Birkeland Centre for Space Sciance at the University of Bergen, Norway.

EGU for Early Career Scientists

EGU for Early Career Scientists

Are you a student, or have obtained a MSc or PhD degree within the past 7 years? If yes, you are an Early Career Scientist! In the EGU we take great care of the young scientists, and offer a wide range of opportunities, mostly associated with the General Assembly. My name is Jone Peter Reistad and I am the Early Career Scientist (ECS) representative in the Solar-Terrestrial division. My role is to make the ECS aware of the opportunities and activities that EGU offers to the scientists of the future, as well as engaging in creating and shaping the ECS venue.

The purpose of this blog-post is to draw your attention to the upcoming General Assembly in April next year. This might sound distant, but you should definitely start thinking about this now! Let me explain why: first of all, the EGU General Assembly is a special meeting for ECSs. Actually, more than 50 % of the meeting participants are covered by the ECS definition. During the last years there has been an increasing effort to make the General Assembly more relevant for ECS. There are numerous Short Courses addressing practical skills (both general and more division specific), hot topics, and other challenges that ECS face. Furthermore, social events such as the icebreaker reception, a networking reception, and the ECS forum, are held during the week. For these reasons, the EGU General Assembly is a highly relevant, and in my opinion outstanding meeting for Early Career Scientists to attend.

But why consider going to EGU now? The regular abstract deadline is January 10, however, if you send in your abstract by December 1st, you can apply for Early Career Scientist’s Travel Support. This will potentially cover your registration and abstract fee in addition to travel expenses up to 300. December 1st is only a few weeks ahead, so do not hesitate to submit your abstract and apply for travel funds.

Of special relevance to our Solar-Terrestrial ECS readers is a Short Course we will run now for the fourth time: “Meet the Experts: The future of Solar-Terrestrial research”. Being an Early Career Scientist, it is often hard to identify which questions are new and what has been answered before. In this short course we invite a panel of renowned researchers. They will give their view on how far we have come in our understanding, and most importantly, on what challenges lie ahead for the young scientists to embark upon. This is an excellent opportunity to meet with the experts and discuss the future of our community.

We are currently a team of 5 people involved in making the Solar-Terrestrial division, especially the General Assembly, more relevant for ECS. If you have any ideas to what could be done, or want to contribute in any way, please send me a notice to ecs-st@egu.eu.

The 2017 solar eclipse and scientific discoveries

The 2017 solar eclipse and scientific discoveries

The next solar eclipse is upon us. On August 21 the moon will pass between the Sun and an observer’s point of view in America and block out daylight, creating an eerie gloom in the sky. The transit of the moon between the Earth and Sun occurs about every 18 months, but for your particular city it can take several hundreds of years before a new eclipse occurs. The figure below shows the paths of all solar eclipses that occurred or will occur during the 2001 to 2020 period. Few eclipses happen around the North or South pole due to the orbital geometry of the heavenly bodies, so proportionally the odds are higher to experience midday darkness if you live at low or mid latitudes. However, since about 71% of the Earth’s surface is covered with water, most of these eclipses occur at places where no one lives and go by unnoticed. Unless you travel to them!

People have long been fascinated by solar eclipses and records in history have been found as early as 2000 B.C. Throughout history researchers and science enthousiasts have travelled the world to watch eclipses, endeavours which were much more difficult in the early days than with nowadays commercial flights. Maybe you are travelling as well to watch this eclipse.

Paths of total and annular solar eclipses during the 2001-2020 period. Credit: Fred Espenak, NASA/GSFC Emeritus

By studying the sun and the eclipses, scientists can look at features of the solar atmosphere that are otherwise hard to observe from the ground due to the intense brightness of the Sun. Discoveries made during eclipses include observations of the outer parts of the solar atmosphere (solar corona), flames of fire from the sun (prominences, jets), radiation other than visible light (infrared, UV) and otherwise invisible comets travelling around the Sun. During the 1868 eclipse a yellow spectral line was discovered by J. Lockyer in the solar chromosphere from a yet unknown chemical element that turned out to be one of the most abundant chemical species in our universe. He named it after the Greek word for the sun (helios) and it took until 1895 before helium was discovered on Earth.

Even today, scientific knowledge is being advanced by studying the solar eclipse and the effects on our nearby space environment and Earth’s atmosphere. When the moon eclipses the Sun, the illumination over a localised region will change rapidly and Earth’s atmosphere will react to this decrease in solar energy. One such reaction that occurs is in the ionosphere, the higher most reaches of the atmosphere. Solar ultraviolet radiation creates a dynamic layer of charged particles that reflect telecommunication transmissions at very low frequencies around the world. Understanding how this layer reacts to changes in solar radiation can enhance our understanding of the ionosphere and hopefully improve the region’s dynamics in model simulations. The direct blocking of radiation will also have a profound effect on the total amount of radiation that is received by the surface as well on the amount that is reflected back to space by the oceans, clouds and atmosphere. Changes in this radiation budget can in a unique way be investigated during the solar eclipse. Studying these variations, in for example temperature or radiation, during an eclipse are useful to test our current understanding of the Sun’s effect on the atmosphere.

Not only academics, but also citizens can contribute to advances in solar-terrestrial science. The Megamovie project aims to create an open-source archive of nearly 1.5 hours continuous solar eclipse. With this dataset new features in the solar corona on long and short time scales will hopefully be discovered.

So, what will you do on 21 August 2017? Watching the eclipse from your hometown, travelling to the path of totality from across the world or take part in any scientific contribution as citizen or researcher? Hopefully you will enjoy the magical moment and experience something new!

For more information: 

http://www.mreclipse.com/Totality2/TotalityApH.html

https://eclipse2017.nasa.gov/science-ground

https://eclipse.gsfc.nasa.gov/solar.html

Welcome

Welcome to the ST division blog!

The Solar-Terrestrial (ST) Division of European Geosciences Union (EGU) is starting its own blog! The blog is an initiative by a group of enthusiasts who met during the EGU’s General Assembly in April 2017. We are thrilled to set up this blog that will keep our readers informed about a range of topics relevant to the science of the division.

A CME from the Sun heading towards the Earth. Thanks to the magnetic field enveloping the Earth, we stay protected from the wrath of the Sun.
Credit: Adapted from NASA/Steele Hill

The influence of the Sun on the Earth and our planetary system have shaped a dynamic, constantly evolving scientific area. The Earth’s atmosphere, ionosphere and magnetosphere are strongly moulded by the Sun, solar wind and galactic cosmic rays. We have an armada of spacecrafts and detectors on the ground to record solar eruptive events and their in-situ manifestations. This helps us study the ST sciences.

The Sun fosters life on Earth and acts as the vitalizer of our very existence. However, it spews large amounts of plasma and energy towards the Earth that can hinder day-to-day life in modern society.

Space weather and terrestrial weather are continually influenced by small changes in solar output, which not only varies from day to day but also through longer timescales throughout its lifetime. Studying the Sun and its effects on the near-Earth environment can facilitate more accurate predictions of space and terrestrial weather. Such forecasting can in turn help keep life on this planet safe by having early warning systems.

Research in the ST sciences is very stimulating for us and we wish to share our enthusiasm with our readers. Bringing science to the public is the intent of this blog. Students as well as early career scientists (ECS) will greatly benefit from the broad nature of topics that will be discussed here. Getting everyone excited about science in general and ST studies in particular is our aim. We will discuss papers in the “spotlight” to look at the recent breakthroughs in this field. There will be articles and interviews of featured scientists to discuss post-doc life, career path or alternative careers.

As well as  exciting scientific topics we will also provide informative general highlights and timely deadlines for conferences. From time-to-time our own EGU-ST ECS representative (Jone Reistad) will discuss ECS related opportunities and problems. All in all, this will be a voice for scientists to reach out to the community.

We have planned an extensive series of blogs from our team of experts and other scientists (especially ECSs and students). We encourage guest bloggers to contact the editor. Come back every month for a new and informative blog post.

 

This text was prepared by Kamalam Vanninathan and Athanasios Papaioannou