New Solar Orbiter data reveals the sun at its quietest

Three of the Solar Orbiter spacecraft’s instruments, including Imperial’s magnetometer, have released their first data.

The European Space Agency’s Solar Orbiter spacecraft launched in February 2020 on its mission to study to Sun and it began collecting science data in June. Now, three of its ten instruments have released their first tranche of data, revealing the state of the Sun in a ‘quiet’ phase.

Solar Orbiter is living up to its promise. We always knew it was going to be a fantastic mission and the early measurements are showing just how much potential there is for unprecedented insights into the Sun. Professor Tim Horbury

The Sun is known to follow an 11-year cycle of sunspot activity and is currently almost completely free of sunspots. This is expected to change over the coming years as sunspot activity ramps up, causing the Sun to become more active and raising the chances of adverse ‘space weather’ events, where the Sun releases huge amounts of material and energy in solar flares and coronal mass ejections.

The Sun’s activity is closely linked to the state of its magnetic field, and this is measured by Imperial’s instrument aboard Solar Orbiter, the magnetometer (MAG). Since June, MAG has recorded hundreds of millions of ‘vectors’ – measurements of the direction and strength of the Sun’s magnetic field.

Solar Orbiter has already flown inside the orbit of Venus, collecting some of the closest data to the Sun so far, and will get progressively closer in the coming years. It is currently orbiting close to the equator of the Sun, which in times of high activity would show a very warped magnetic field.

Currently, however, the Sun’s magnetic ‘equator’ is lying very flat to the true equator, allowing the spacecraft to observe fields from the Northern magnetic hemisphere for weeks on end, when just a few degrees north of the equator. Near times of high solar activity, when the Sun’s magnetic equator is more warped, it is not possible to see a single polarity of magnetic field for so long.

Solar wind structure

The MAG has also observed waves caused by protons and electrons streaming from the Sun. Further out, near the Earth, these particles are distributed more evenly in the bulk solar wind of charged particles streaming from the Sun, but at Solar Orbiter there are also ‘beams’ protons and electrons coming from the Sun.

There appears to much more structure in the solar wind closer to the Sun, and this is further shown by MAG confirming the presence of ‘switchbacks’ – dramatic folds in the solar wind first recorded by the Parker Solar Probe, a NASA mission launched in 2018.

Solar Orbiter and Parker Solar Probe will work together over the coming years to compare data on the same phenomena at different distances and orbits around the Sun as it wakes up and enters the next phase of its sunspot cycle.

Overview of the Solar Orbiter magnetic field data released today. Here, the amplitude of the magnetic field is shown, along with the distance of the spacecraft from the Sun in Astronomical Units (the Earth is 1 AU from the Sun). The magnetic field is larger closer to the Sun, but the magnetic fields measured in space by MAG are still less than a thousandth of the Earth’s magnetic field

A testament to hard work

The data released today are part of Solar Orbiter’s commitment to releasing data within three months of it arriving on the ground – a tight schedule for any space mission, but particularly challenging during a pandemic. Professor Tim Horbury, the Principal Investigator of MAG from the Department of Physics at Imperial, says that the fact the data is ready on time is testament to the hard work of the engineering team at Imperial.

“They have worked incredibly hard over the last few months. It’s been an immense amount of work,” he said. But it’s paid off. “There’s a lot of it that we’re releasing that nobody’s really looked at in great detail yet. So I am sure there will also be a whole extra set of wonders – we just don’t know what they are yet. There’s an enormous amount for people to do, and I really hope that people will dive in.”

MAG has been performing brilliantly for seven months now. We tested it here on Earth before launch, but we cannot perfectly recreate the harsh space environment, and certainly not for the prolonged periods MAG is now experiencing. Helen O’Brien

One of the first challenges from the team was to eliminate the tiny magnetic field signatures from the spacecraft itself. Almost everything that runs on electrical power on the spacecraft creates a varying magnetic field that must be removed from the data in order to get the true signal from the Sun. This includes the solar panels, the thrusters, the other science instruments and over 50 separate heaters.

While different parts of the spacecraft turned on, the team had to take data from all of them in order to eliminate their signal. But Professor Horbury says it was all worth it: “This is just the beginning, but the data is already enormously exciting and very rich.

“Solar Orbiter is living up to its promise. We always knew it was going to be a fantastic mission and the early measurements are showing just how much potential there is for unprecedented insights into the Sun,” he said.

MAG Instrument Manager Helen O’Brien said: “MAG has been performing brilliantly for seven months now. We tested it here on Earth before launch, but we cannot perfectly recreate the harsh space environment, and certainly not for the prolonged periods MAG is now experiencing.

“So to see the first data go public is wonderful, and this is just the beginning. In December, the spacecraft does a flyby of Venus, and then we are back in to half the Sun-Earth distance in February next year. We are so proud!”

31 thoughts on “New Solar Orbiter data reveals the sun at its quietest

  1. I you want to see where the Solar Orbiter and the Parker Solar Probe are at any point now or past or future, the link below is to the Stereo mission where you can draw a plot of hwere they are at any mission time.
    https://stereo-ssc.nascom.nasa.gov/cgi-bin/make_where_gif

    Just select which probes you want to draw in addition to the Stereo A/B positions. Select a date/time, or let it default to current.
    PSP just finished a very close-in solar pass (3 1/2 days ago) near the Sun at 0.09465 AU on September 27, 0900 UTC.
    The SO orbiter is out near 1 AU (0.983 AU) at the moment, about 128º ahead of Earth’s always-defined 0º heliographic longitude.

  2. Currently, however, the Sun’s magnetic ‘equator’ is lying very flat to the true equator, allowing the spacecraft to observe fields from the Northern magnetic hemisphere for weeks on end, when just a few degrees north of the equator. Near times of high solar activity, when the Sun’s magnetic equator is more warped, it is not possible to see a single polarity of magnetic field for so long.
    This called the Rosenberg-Coleman effect. And is usually seen around solar minimum [sometimes just after],
    https://leif.org/research/Asymmetric-Rosenberg-Coleman-Effect.pdf
    It also has an effect on Cosmic Rays:
    https://leif.org/research/Anomalous-Cosmic-Ray-Anisotropy-1954.pdf

    • Leif, thanks for the info. I greatly appreciate your comments as I have learned more about our Sun and its effects on Earth and the rest of the solar system than I did back in my school days. (Of course I am ancient…maybe even ancienter than you!)

  3. Has anyone seen a more extensive video of the solar “campfire” nanoflares? The only public stuff is a loop of uncertain total length and playback speed. I don’t see how such small and directed flares occur spontaneously from any MHD processes. I have seen no speculation other than Eugene Parker’s original suggestions for coronal heating.

  4. This is science,exploring our universe at it’s finest.
    Every thing new we learn,opens a thousand new questions..
    And I love the graphics this data allows..
    It will be very interesting to see how our understanding of the sun and solar events,improves,expands and backflips..

    Now being older and even more cynical than when we put men on the moon,I wonder how far into the next solar cycle we will be ,before some “Climatologist Style” science person gomms unto a new observation and predicts the “Solar Ozone Hole equivalent” which ,of course,dooms us all unless we radically change our evil consumer ways..
    This new and exciting doom will,like climatology,be due to a poor thinker,imposing linear interpretations of cyclic events.

    We could run a betting pool,but if the stakes got too inviting any visitor here could write the narrative ,using old fear media boiler plate..

    • Well, it makes much more sense for it to use solar power than it does for us here on Earth, because Earth doesn’t keep blocking its sunlight.

    • Hopefully, they also added some wind power equipment.

      Just imagine how much energy you could harness from the solar wind at that distance 🙂

      This wind power is absolutely essential to keeping the spacecraft operational, since the solar PV panels don’t work at night 🙂 🙂

      / Greta Thunberg’s science tutor / off

      • Hi Matthew, I sense that might be a ‘trick’ question.
        During solar minima there is always overlap of spots with polarity of both the preceding and succeeding cycles. Solar scientists take for the minimum a date (month) when prevalence of the first is taken over by the second, but that is not always easy to determine.
        As long as the SSN count is bouncing up and down without major or frequent excursion from the single digits (using uncorrected Wolf count), for my own personal consideration, I take it to be the solar minimum associated with the outgoing cycle, despite likely presence or even majority of spots belonging to the forthcoming cycle. Having above in mind, my answer is: the present ‘minimum’ (the bottom or floor) of the current solar activity) started in November 2017 and is still ongoing.
        p.s. In my personal notes I like to refer to it as the ‘solum’, using play on the ‘sol’. In Latin the ‘sun’ is ‘solis’, but also the noun ‘solum’ can mean bottom, floor or ground, hence ‘sole’ of the foot or shoe ‘sole’.

    • Yes, all the spotted sunspots in the last month or two had latitude and magnetic signature of the new SC25 cycle, but that doesn’t mean the current minimum is over. btw. September count is less than one (<1)

    • Maybe deep slumber and zero are not quite the same. They say “Although we’ve seen a steady increase in sunspot activity this year, it is slow.”.

        • My forecast as of today is 128+/-10.
          This is based on the WSO polar fields up to the Minimum in December 2019.
          Later this week I’ll post a paper on how I got to my prediction.
          This from the Conclusion:
          “That solar cycle prediction is still in its infancy is borne out by the extreme range of predictions of Cycle 25 (Pesnell, 2020; see Figure 5 below) indicating that we have not made much progress (if any) since predictions were made of Cycle 24 (Pesnell, 2016), which showed a similar spread (from half to double of actual value observed). With such a wide spread (from 50 (Kitiashvili, 2020) to 233 (McIntosh et al., 2020)), someone or even several ones are bound to be ‘correct’, regardless of the possible correctness of the method used. The many non-overlapping error bars illustrate the folly of even assigning error bars to the predictions or, at least, to believe in them. ”
          Caption to a Figure (I am still waiting for permission to show it):
          “The 38 predictions of Solar Cycle 25 that had been registered by January 2020 (Adapted after Pesnell (2020), with permission). The various method categories employed by authors of the predictions are indicated by different colors. Our prediction (128±10) is indicated by the yellow ‘sun’ in the center of the plot, near the average (123±21) of the 6 (now 7) precursor methods that seem to be preferred. The overall average is 132±47 (median 124). None of these numbers are substantially different, so one could perhaps just go with the “Wisdom of the Crowd” (Aristotle, 350 BCE, “Politics”, III:xi).”

          • Thank you Dr. Svalgaard.
            My expectation (in contrast to the above) is ‘substantially different’, not much of fun being part of a crowd.
            Keep safe.

          • Aristotle: “it is possible that the many, though not individually good men, yet when they come together may be better, not individually but collectively, than those who are so, just as public dinners to which many contribute are better than those supplied at one man’s cost” wikipedia

          • I just looked for the daily TCI values presented at spaceweather.com.
            There I found at July 13th the lowest value expressed as “power (10 11 W)
            (7.0000000-13.000000-2020.0000 2.3431799e+10)

            Has that some informative value in concern of the new cycle to begin ?

          • Prediction of solar cycle is an important goal of Solar Physics both because it serves as a touchstone for our understanding of the sun and also because of its societal value for a space faring civilization. The task is difficult and progress is slow. Schatten et al. (1978) suggested that the magnitude of the magnetic field in the polar regions of the sun near solar minimum could serve as a precursor for the evolution and amplitude of the following solar cycle. Since then, this idea has been the foundation of somewhat successful predictions of the size of the last four cycles, especially of the unexpectedly weak solar cycle 24 (“the weakest in 100 years”). Direct measurements of the polar magnetic fields are available since the 1970s and we have just passed the solar minimum prior to solar cycle 25, so a further test of the polar field precursor method is now possible. The predicted size of the new cycle 25 is 128±10 (on the new sunspot number version 2 scale), slightly larger than the previous cycle.
            Vuk: by definition you are part of the crowd.

          • Sounds like it’s time for a pool. Not sure if anyone has the patience to wait five years for the winner, though

  5. The Sun is known to follow an 11-year cycle of sunspot activity and is currently almost completely free of sunspots. This is expected to change over the coming years as sunspot activity ramps up, causing the Sun to become more active raising the chances of adverse ‘space weather’ events, where the Sun releases huge amounts of material and energy in solar flares and coronal mass ejections.”

    And of course, anything that represents a bang in space is bad.

  6. From the above article: “The Sun is known to follow an 11-year cycle of sunspot activity and is currently almost completely free of sunspots. This is expected to change over the coming years as sunspot activity ramps up . . .”

    But we previously had this: “Solar Cycle 25 is officially underway. NASA and NOAA made the announcement during a media teleconference earlier today. According to an international panel of experts, sunspot counts hit rock bottom in Dec. 2019, and have been slowly increasing since.” —https://wattsupwiththat.com/2020/09/15/solar-cycle-25-has-officially-begun/

    Science is so unsettled.

  7. One of the first challenges from the team was to eliminate the tiny magnetic field signatures from the spacecraft itself.

    Along with the article it would be interesting how they did that with varying field.

    • Was it actually to “eliminate” the tiny magnetic field or, instead (and much more easily implemented), to calibrate the spacecraft’s intrinsic, non-isotropic magnetic field so that it could be mathematically subtracted for the data measurements?

      • I had assumed that’s what they actually meant. They were accounting for onboard magnetic fields and removing it from the readings.

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