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Savvas Raptis

@savvasraptis.bsky.social
97 followers 87 following 30 posts

Researcher at Johns Hopkins University Applied Physics Laboratory (JHUAPL): savvasraptis.github.io

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Savvas Raptis @savvasraptis.bsky.social · 15/09/2026
I support Wikipedia, where information is still human-created, fact-checked, and 100% free. Join me! donate.wikimedia.org
donate.wikimedia.org
Make your donation now - Wikimedia Foundation
Donate to the Wikimedia Foundation, the nonprofit that hosts Wikipedia and other crucial free knowledge projects. Each year, the generosity of the 2% of readers who donate allows us to expand the reac...
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Savvas Raptis @savvasraptis.bsky.social · 12/09/2026
Grad students in geospace science: the CGS Fellowship is open. $10-12K, great variety of research topics (including one from me). Due Oct 23: cgs.jhuapl.edu/Resources/Ag...
cgs.jhuapl.edu
Thursday, October 1, 2026 - Sunday, August 1, 2027
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AGU (American Geophysical Union) @agu.org · 12/09/2026
🙋‍If you are an AGU member who has attended an Annual Meeting in the last five years, you are eligible to volunteer for the OEP Program. Volunteers will give feedback on presenters’ draft presentations in November. You do not need to attend AGU26 yourself to volunteer. ️spklr.io/63328ET3hy
🌉 If you are an AGU member who has attended an Annual Meeting in the last five years, you are eligible to volunteer for the OEP Program. Volunteers will give feedback on presenters’ draft presentations in November. You do not need to attend AGU26 yourself to volunteer.
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Christopher Chen @chkchen.bsky.social · 28/07/2026
A postdoc position is available on my STFC-funded research project. Deadline 28 August 2026, start date flexible but available immediately. Enquiries welcome. More info and application: qmul-jobs.tal.net/vx/candidate...
qmul-jobs.tal.net
Quick Check Needed
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Savvas Raptis @savvasraptis.bsky.social · 18/07/2026
Great GEM workshop last week in Portland, Maine. Our focus group on Multiscale Dayside Transients (MDT) ran strong sessions on how transients interact with the bow shock and magnetosphere. Thanks to all who presented, and stay tuned for our GEM challenge. gemworkshop.org
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Savvas Raptis @savvasraptis.bsky.social · 10/07/2026
The @agu.org Annual Meeting in San Francisco is approaching! Our session on "Collisionless Shocks in Heliospheric and Astrophysical Plasmas" (SH010) is open for abstract submissions: agu.confex.com/agu/agu26/pr... #AGU26 #Heliophysics #SpacePhysics #Astrophysics
agu.confex.com
Collisionless Shocks in Heliospheric and Astrophysical Plasmas and their Effects on Particle Acceleration and Planetary Magnetospheres
Collisionless shock waves are ubiquitous across the universe, appearing in plasmas from planetary environments to supernovae. Upstream, a variable foreshock forms where waves and particles interact in...
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Nature Portfolio @natureportfolio.nature.com · 15/06/2026
NASA’s Juno observations show relativistic electron acceleration at the bow shock of Jupiter and establish a universal scaling law linking shock size to maximum cosmic ray energy, according to a paper in Nature. go.nature.com/49ArfuL 🔭🧪
This is Extended Data figure 2, which shows a schematic representation of efficient particle acceleration within a foreshock transient.
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Eos @eos.org · 11/06/2026
Forecasting space weather, from routine and quiet to rare and extreme, requires tracking conditions across tens of millions of kilometers of interplanetary space, write @savvasraptis.bsky.social and colleagues @jhuapl.bsky.social. eos.org/science-upda...
eos.org
Vast Space, Sparse Data: An AI Answer to Twin Space Weather Challenges - Eos
Modern machine learning and AI methods can help heliophysics researchers and space weather forecasters overcome limitations from a dearth of observations and the infrequency of extreme events.
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Savvas Raptis @savvasraptis.bsky.social · 11/06/2026
New article in @agu.org's EOS out today! Space is huge and our data is sparse, while extreme events are rare. So how do we forecast space weather reliably? AI and ML are part of the answer! Read it: eos.org/science-upda... #SpaceWeather #Heliophysics
eos.org
Vast Space, Sparse Data: An AI Answer to Twin Space Weather Challenges - Eos
Modern machine learning and AI methods can help heliophysics researchers and space weather forecasters overcome limitations from a dearth of observations and the infrequency of extreme events.
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Nature Portfolio @natureportfolio.nature.com · 04/06/2026
NASA’s Juno observations show relativistic electron acceleration at the bow shock of Jupiter and establish a universal scaling law linking shock size to maximum cosmic ray energy, according to a paper in Nature. go.nature.com/49ArfuL 🔭🧪
This is Extended Data figure 2, which shows a schematic representation of efficient particle acceleration within a foreshock transient.
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Nature @nature.com · 04/06/2026
Nature research paper: Relativistic electron acceleration at the bow shock of Jupiter and beyond go.nature.com/49GdTx4
go.nature.com
Relativistic electron acceleration at the bow shock of Jupiter and beyond - Nature
NASA’s Juno observations show relativistic electron acceleration at the bow shock of Jupiter and establish a universal scaling law linking shock size to maximum cosmic ray energy.
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Savvas Raptis @savvasraptis.bsky.social · 03/06/2026
New in @nature.com : Using #NASA 's Juno and JEDI instrument from @jhuapl.bsky.social we show Jupiter's foreshock accelerates electrons to near light speed. Using our solar system observations, we built a scaling law from planetary shocks to supernova remnants. www.nature.com/articles/s41...
nature.com
Relativistic electron acceleration at the bow shock of Jupiter and beyond - Nature
NASA’s Juno observations show relativistic electron acceleration at the bow shock of Jupiter and establish a universal scaling law linking shock size to maximum cosmic ray energy.
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ESA Space Science @science.esa.int · 19/05/2026
What is Smile set out to discover? This groundbreaking mission will observe Earth’s magnetosphere in X-rays while capturing the northern lights in ultraviolet, offering an entirely new way to see how our planet defends itself from solar storms. 🔭 🧪 ☀️
In the background of this infographic is an artist impression of the interaction between the Sun and Earth, in the sense that the Sun is sending out particles and the Earth is holding up a shield against them. Three pop-out boxes indicate the top three questions that Smile seeks to solve, with close-up images of the relevant part of the Sun-Earth connection.
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Savvas Raptis @savvasraptis.bsky.social · 19/05/2026
I support Wikipedia, where information is still human-created, fact-checked, and 100% free. Join me! donate.wikimedia.org
donate.wikimedia.org
Make your donation now - Wikimedia Foundation
Donate to the Wikimedia Foundation, the nonprofit that hosts Wikipedia and other crucial free knowledge projects. Each year, the generosity of the 2% of readers who donate allows us to expand the reac...
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ESA Space Science @science.esa.int · 19/05/2026
Smile begins her mission! 🙌 The Inspector is on her way to reveal how exactly Earth’s invisible shield protects us against the solar wind! www.esa.int/Science_Expl... 🔭 🧪 ☀️
A tall, slim rocket is lifting off from a launchpad. Bright light bursts from the bottom of the rocket, and smoke billows all around the lower half of the frame.
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Savvas Raptis @savvasraptis.bsky.social · 12/05/2026
Earth's bow shock has two faces: peaceful (quasi-perpendicular) and chaotic (quasi-parallel). The magnetosheath holds the clues to understand its processes! Our team needs your help on @zooniverse.bsky.social Intro: youtu.be/4MWU7GDIlgs Join: zooniverse.org/projects/vickitoyedens/shock-detectives
youtu.be
Shock Detectives
YouTube video by APL Webinars and Events
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Savvas Raptis @savvasraptis.bsky.social · 01/05/2026
Our latest work is now summarized in ESA Solar Orbiter Science Nugget #88! We compared foreshocks of interplanetary and planetary shocks using Solar Orbiter + NASA MMS. see the science nugget at : www.cosmos.esa.int/web/solar-or... #ESA #NASA #SolarOrbiter #Heliophysics #PlasmaPhysics
cosmos.esa.int
Science nugget: Compressive Structures in the Foreshock of Collisionless Shocks - Solar Orbiter - Cosmos
The goal of this study is to explore this apparent discrepancy by examining a high-Mach-number quasi-parallel IP shock observed by Solar Orbiter and comparing it with Earth’s bow shock using the Magne...
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Dr Luke Barnard @lukebarnard.bsky.social · 29/04/2026
Looking for a PhD position in solar system science? Consider coming to work with me, @interplanetary.bsky.social and @mathewjowens.bsky.social! We have a project on Solar Wind - Magnetosphere Coupling at the Giant Planets. www.findaphd.com/phds/project... #heliophysics#aurora#spaceweather
findaphd.com
Solar Wind – Magnetosphere Coupling At The Giant Planets at University of Reading on FindAPhD.com
PhD Project - Solar Wind – Magnetosphere Coupling At The Giant Planets at University of Reading, listed on FindAPhD.com
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AGU (American Geophysical Union) @agu.org · 15/04/2026
⏳ One week left to submit a session, town hall, or scientific workshop proposal for #AGU26! 🗣️➡️ Add your voice to the conversation at AGU26: Where Science Connects. Submit a proposal by 22 April: buff.ly/1sPRVfF
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Savvas Raptis @savvasraptis.bsky.social · 30/03/2026
Why foreshocks of IP shocks and Earth's bow shock look different? In our new paper, we show that they initiate the same way, but observational constraints and global shock geometry get in the way. Read the full study here: doi.org/10.3847/2041... #Heliophysics #MMS #SolarOrbiter
doi.org
Compressive Structures in the Foreshock of Collisionless Shocks
Compressive Structures in the Foreshock of Collisionless Shocks, Raptis, Savvas, Trotta, Domenico, Turner, Drew L., Blanco-Cano, Xóchitl, Hietala, Heli, Karlsson, Tomas, Jebaraj, Immanuel Christopher,...
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Savvas Raptis @savvasraptis.bsky.social · 05/03/2026
New paper out in Science Advances addressing a long-standing open question: what is maximum energy of particles in radiation belts? A simple model shows a universal energy limit of 7 ± 2 TeV, with implications for cosmic rays. doi.org/10.1126/scia... #Heliophysics #Astrophysics #SpaceScience
doi.org
Universal energy limits of radiation belts in planetary and brown dwarf magnetospheric systems
Exoplanetary and brown dwarf radiation belt systems may contribute significantly to observed cosmic ray spectra up to several TeV.
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Paul Byrne @theplanetaryguy.com · 15/12/2025
Shout-out to @alexwitze.bsky.social for being included in @merriam-webster.com's definition for "heliophysics" (which has long been a word, but is now a *recognised* word)
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Savvas Raptis @savvasraptis.bsky.social · 14/12/2025
#AGU25 starts tomorrow! I'll be around all week! Hope to see many people there and catch up👋!
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Savvas Raptis @savvasraptis.bsky.social · 11/12/2025
NASA just selected @jhuapl.bsky.social Developed CINEMA Mission! www.nasa.gov/news-release... ! 🥳
nasa.gov
NASA Selects Two Heliophysics Missions for Continued Development - NASA
NASA has selected one small explorer mission concept to advance toward flight design and another for an extended period of concept development.
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Johns Hopkins APL @jhuapl.bsky.social · 11/12/2025
NASA has selected Dartmouth College and Johns Hopkins APL to begin development on CINEMA, a mission to improve our understanding of the growing impacts of space weather. jhuapl.link/8cb
jhuapl.link
NASA Selects Johns Hopkins APL-Developed CINEMA Mission to Study Space Weather
CINEMA, a mission to improve understanding of the growing impacts of space weather, has been competitively selected by NASA for development.
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Florian Koller @flokoller.bsky.social · 09/12/2025
Join in for our first EHC HelioMeet seminar today! Looking forward to seeing you there! www.heliophysics.eu/heliomeet
heliophysics.eu
EHC - HelioMeet
HelioMeet - an EHC seminar series Come for the interdisciplinary science — stay for the behind-the-scenes insights into navigating scientific life in the heliophysics community. HelioMeet is a semin...
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Vincent Ledvina @vincentledvina.bsky.social · 03/12/2025
This is how it feels right now...
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Savvas Raptis @savvasraptis.bsky.social · 05/11/2025
A huge thanks to all participants for making the 3rd LMAG25 workshop a success! For anyone who wants to revisit the talks: The final program & presentation recordings are now available on our site: www.lmag25.com/presentations #geospace #heliophysics #machinelearning
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Savvas Raptis @savvasraptis.bsky.social · 31/10/2025
Yesterday I joined remotely a space weather AI/ML panel at #ESWW2025 in Umeå as a giant face on a screen. Key takeaways: We need less hype, more rigor. Better validation, standardized benchmarks, and open access to models/data. Hope to join in-person next year😀!
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Savvas Raptis @savvasraptis.bsky.social · 30/08/2025
Heading to Lisbon for #IAGA2025! I'm giving three talks: • Mon 17:15 (C.2.22): Particle acceleration at bow shocks • Tue 11:45 (C.3.7): Storm-time plasma sheet convection • Tue 16:30 (C.2.22): An update from the #NASA CGS drive center Come say hi if you're around! #Heliophysics #Geophysics
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AGU (American Geophysical Union) @agu.org · 12/08/2025
Know a dataset making an impact for people, planet, or prosperity? 🌎 Nominate it for AGU’s upcoming commentary by 10 Oct. You may be featured! 🔗: buff.ly/XLFfYqM #ImpactfulData #EarthScience
docs.google.com
Nominate an Impactful Dataset
You are invited to nominate a dataset to be included in a commentary about the impact of Earth, space, and environmental data using the dimensions of people, planet, and prosperity. Selected…
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Savvas Raptis @savvasraptis.bsky.social · 15/07/2025
Our session on the upcoming @agu.org Annual Meeting is open for abstract submission: "Collisionless Shocks in Heliospheric and Astrophysical Plasmas and their Effects on Planetary Magnetospheres". Deadline: 30 July 2025 (23:59 EDT) #AGU25 agu.confex.com/agu/agu25/pr...
agu.confex.com
Collisionless Shocks in Heliospheric and Astrophysical Plasmas and their Effects on Planetary Magnetospheres.
Collisionless shock waves are ubiquitous across the universe, manifesting in diverse astrophysical plasmas, from planetary environments to supernovas. Upstream of shocks, a variable foreshock emerges,...
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Dr. David Miller 🏳️‍🌈 @davidimiller.bsky.social · 10/07/2025
🧪 BREAKING (good news): Senate subcommittee says NO! to Trump's proposed slashes to NASA & NSF funding. Today, the subcommittee said to keep NASA + NSF funding at $33.9 billion, the same as in FY24. See 7:15 below. Full Senate appropriations committee meets tomorrow about it. 🧵 1/3
appropriations.senate.gov
Subcommittee Markup of the Commerce, Justice, Science, and Related Agencies Appropriations Act | United States Senate Committee on Appropriations
United States Senate Committee on Appropriations
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Vincent Ledvina @vincentledvina.bsky.social · 01/07/2025
A large coronal hole is currently facing Earth! We may see high-speed solar winds and minor-moderate geomagneitc storms towards the end of the week. #heliophysics
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Savvas Raptis @savvasraptis.bsky.social · 01/07/2025
Just came back from NSF/GEM 2025 last week in Iowa, Des Moines (gemworkshop.org)! Exciting talks, new ideas, and the launch of our focus group on Multiscale Dayside Transients. Had a great time with friends and colleagues and already looking forward to next time!
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Imogen Gingell @ilgingell.bsky.social · 24/06/2025
I'm excited to announce my passion project JourneyMon: Monster Trainer Roleplaying is coming soon to Kickstarter! Be sure to follow our pre-launch page to keep up to date with the latest news! www.kickstarter.com/projects/ilg...
kickstarter.com
Coming soon: JourneyMon: Monster Trainer Roleplaying
A narrative, collaborative world-building TTRPG about friendship and monster battles.
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Jessica Lu @jluastro.bsky.social · 20/06/2025
NASA Goddard is pushing through a 48% staff reduction!!! This could impact the upcoming Roman Space Telescope and many other future Astro missions. News coverage seems not sensational enough. Are we really going to let NASA (as we know it) die quietly? www.space.com/space-explor...
space.com
NASA begins push to slash workforce with more staff buyouts, early retirements as budget cuts loom
NASA employees have until July 25 to decide if they'll stay or go.
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Paul Byrne @theplanetaryguy.com · 05/06/2025
You've heard about the catastrophic cuts to U.S. scientific leadership the Trump Administration has proposed. This chart from Joshua Weitz (joshuasweitz.bsky.social‬) shows just how bad it is—funding levels for NASA, NSF, and NIH so low as to destroy science in America. CALL YOUR REPRESENTATIVES!
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AGU (American Geophysical Union) @agu.org · 05/06/2025
From Alaska and Hawaii to Florida and New York, scientists made their voices heard on Capitol Hill today—because the stakes are high. 🌎 🔭 🌌 🛰️
Congressional visit day participants take a group photo.
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ESA Space Science @science.esa.int · 04/06/2025
Meet Smile. The soon-to-be newest member of our space science mission fleet. Employing X-ray and UV vision to see how Earth reacts to relentless streams and bursts of particles from the Sun. Dive into the mission here 👉 www.esa.int/Science_Expl... 🔭🧪 #planetsci
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Paul Byrne @theplanetaryguy.com · 31/05/2025
Inspired by @jtuttlekeane.bsky.social and @ohdearz.bsky.social, here's what the White House proposed budget cuts to NASA would do to the entirety of the agency's Science Mission Directorate. Bloodbath is right.
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Bailey Bowcutt @baileybowcutt.bsky.social · 22/05/2025
I'm a current Harvard graduate student and I found out today that I had my NSF GRFP terminated without notification. I was awarded this individual research fellowship before even choosing Harvard as my graduate school
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Savvas Raptis @savvasraptis.bsky.social · 19/05/2025
Had a fantastic week in Paris celebrating the 10th anniversary of #NASA's Magnetospheric Multiscale (MMS) mission 10thmmsanniv.sciencesconf.org ! The workshop featured excellent talks and discussions! Looking forward to next year’s gathering! #heliophysics #research #space
10thmmsanniv.sciencesconf.org
10th MMS anniversary - 11th MMS community workshop - Sciencesconf.org
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Savvas Raptis @savvasraptis.bsky.social · 10/05/2025
Great week at @iwf-oeaw.bsky.social, reconnected with friends and colleagues and had insightful discussions. Thanks for hosting! Looking forward to my next visit and to seeing you in Paris next week for the #MMS Anniversary Workshop. #Heliophysics #Collaboration
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Savvas Raptis @savvasraptis.bsky.social · 01/05/2025
Our collisionless shocks session at #EGU25 drew a great crowd, sparked insightful discussions and set the stage for new #heliophysics collaborations. Thanks to everyone that attended!
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Savvas Raptis @savvasraptis.bsky.social · 27/04/2025
Arrived in Vienna yesterday for #EGU25! Ready for a week of #Heliophysics, science chats, and reconnecting with colleagues and friends. Let’s grab coffee if you’re around! Find more information about the program www.egu25.eu and if you are around, please come to my talks and presentations to chat!
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Savvas Raptis @savvasraptis.bsky.social · 26/02/2025
Check our latest research using both #NASA and #ESA space missions on "Multimission Observations of Relativistic Electrons and High-speed Jets Linked to Shock-generated Transients"! doi.org/10.3847/2041... via ApJL of @aas.org #Heliophysics #Astrophysics
doi.org
Multimission Observations of Relativistic Electrons and High-speed Jets Linked to Shock-generated Transients - IOPscienceSearchopens in new tab
Multimission Observations of Relativistic Electrons and High-speed Jets Linked to Shock-generated Transients, Raptis, Savvas, Lindberg, Martin, Liu, Terry Z., Turner, Drew L., Lalti, Ahmad, Zhou, Yufe...
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AGU (American Geophysical Union) @agu.org · 14/02/2025
AGU stands with federal scientists. Read more on fromtheprow.agu.org/standing-tog...
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Savvas Raptis @savvasraptis.bsky.social · 13/01/2025
Thrilled our research on electron acceleration is out in Nature Communications! We show a cross-scale process accelerating electrons to very high energies, revealing how shocks act as natural accelerators across the Universe. www.nature.com/articles/s41... #heliophysics #space #research
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Savvas Raptis @savvasraptis.bsky.social · 28/12/2024
Our review paper on downstream jets is out! We summarize findings from 100s of articles on how jets form at collisionless shocks, their role in planetary systems, and their space weather effects. Many questions remain to explore! Read it here: link.springer.com/article/10.1... #Heliophysics #Space
link.springer.com
Jets Downstream of Collisionless Shocks: Recent Discoveries and Challenges - Space Science Reviews
Plasma flows with enhanced dynamic pressure, known as magnetosheath jets, are often found downstream of collisionless shocks. As they propagate through the magnetosheath, they interact with the surrou...
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