Cosmic radiation in outer and inner space (with some personal - - PowerPoint PPT Presentation
Cosmic radiation in outer and inner space (with some personal reminiscences) Pter Kirly Department of Space Physics and Technology Institute for Particle and Nuclear Physics MTA Wigner RCP ELFT Summer School on Astroparticle Physics
Department of Space Physics and Technology Institute for Particle and Nuclear Physics MTA Wigner RCP
ELFT Summer School on Astroparticle Physics Mátraháza, 3. – 7. September 2018.
What’s in a name? Ionization puzzle -> Höhenstrahlung -> Cosmic rays -> Astroparticles Shifts of emphasis: Ionization, Geo- and HE physics, Space physics, Astrophysics Energy spectra, interactions, composition, directional distributions, origin Terrestrial, atmospheric and magnetospheric effects Sun as a star, heliospheric energetic particles, Voyager and IBEX missions Solar cycle, CR Modulation, Heliosphere, local and farther interstellar, IG medium Early research on cosmic antiparticles, pioneering results of the PAMELA mission Major astroparticle research facilities, and how to proceed
What’s in a name? That which we call a rose By any other word would smell as sweet.
(Shakespeare: Romeo and Juliet)
IUPAP / C4 Astroparticle physics topics: Some remarks:
„Cosmic rays” is obviously a misnomer, created by Millikan in 1925, before the true nature of primaries was revealed, starting in 1929. Long series of conferences, such as ICRC’s (35th in 2017), ECRS’s (26th in 2018), ISVEHCRI (20th in 2018) all have cosmic rays in their name Is „Astroparticle physics” not a misnomer to some extent? Are dark matter, gravity waves and gamma rays really particles? Are secondary CR particles really astroparticles? The name change reflects a shift of emphasis (or of lobbying power?), but conference topics are going to remain, or change only slowly.
Topics of the last International Cosmic Ray Conference I attended
My last European Cosmic Ray Symposia (22nd and 23rd ECRS) in Turku and Moscow, in 2010. and 2012. We hosted the 1988. and 1994. ECRS’s in Balatonfüred. 1994: 2010: Invited talk in 2012: Sam Ting was much amused to see it
Why was it so hard to find the source of ionization in shielded containers?
Victor Hess in 1912
From CRs as particles to big accelerators and space physics (1929-1950’s): Emphasis on high-energy physics and geophysics GM-counter, concidence techniques, Bothe and Kolhörster 1929. Rossi, Auger: extended air showers Carl Anderson, 1932: positron, 1936 muon Blackett and Occhialini, 1932: pair creation Further developments in HE physics: discovery of pion by Occhialini and Powell: 1947 Extensive coincidence work by Jánossy and Rochester in Manchester during the war Rochester and Butler, 1947: discovery of the first strange particles (Kaon, Lambda) Important developments in geophysical and heliospheric applications of cosmic rays Latitude effect, longitude effect, modulation, Forbush effect, underground physics Start of radio work in Jodrell Bank, originally for EAS
After the low luminosity and random directions of cosmic ray secondaries made further HE research difficult, accelerators took over (discoveries of antiprotons and antineutrons). With space age, new perspectives opened for low-energy CR and heliospheric
a role as „poor man’s accelerators”.
Starting from the early sixties, new astronomies (UV, IR, X, Gamma, Nu) were born and came of age, but still kept a close connection to CR physics. Also, magneto- and heliospheric plasma, particles and fields were studied by various missions. One important new field was neutrino physics, where George Marx played a prominent part, starting a new and high-level conference series in Balatonfüred. A picture taken over from a paper by András Patkós. But I am also there, sticking out my head in the back row.
Galactic cosmic ray elemental abundances at GeV energies: evidence for a long time spent in the Galaxy by primordial CRs, interacting with nuclei of the interstellar medium.
Veteránok 2017 Visszaáramló napszél V1 V2
The region of outward streaming solar wind: the Heliosphere.
The supersonic inner region ends in the termination shock, surrounded by the subsonic heliosheath, separated from interstellar plasma by the heliopause.
2-dimensional models of solar wind – interstellar wind interactions (in Axford’s dinner plate and in my kitchen sink)
Veteránok 2017
High-gain antenna Low-energy charged particles UV spectrometer Plasma detector CRs
Electronics Plasma-wave antenna
Magnetometer boom Thermoelectric generator
Veteránok 2017
Dead and still functioning heliospheric spacecraft (should send birthday greetings to Voyager-1 today!) Some other important data for the two Voygers:
End of planetary mission: 1980 for V1, late 1989 for V2, after passing Neptune. V1 crossed termination shock: 15th December 2004, at 94 AU from the Sun V2 crossed termination shock: 30th September 2007, at 84 AU from the Sun V1 crossed the heliopause into interstellar space: 25 September 2012 at 121 AU Power of radio transmitter: 22 W My personal involvement: member of senior review team in Washington, 1995
Veteránok 2017
MeV ion count rates of V1 and V2 before and after the termination shock transits (TS1, TS2), and vanishing counts for V1 beyond the heliopause (HP1).
>70 Mev, mainly cosmic ray intensity variations as seen by V1 and V2 at the same time, but at different solar distances. No big changes are seen at crossing the Termination shock. Forbush effect seen in 2006. Just before and after the heliopause count rates are not correlated.
Solar activity as measured by sunspot numbers, and cosmic ray intensity as measured by a high-latitude neutron monitor (Thule in Greenland).
Veteránok 2017
Memorial tablet for Victor Hess in Bad Saarow-Pleskov, 7 August 2002
Some of the distinguished guests of the centenary celebration
Remarkable coincidences:
Heliospheric MeV ion countrates sharply decreased just before the centenary of CR discovery, indicating an imminent exit of V1 from the Heliosphere at 121.5 Au solar
Veteránok 2017 Behaviour of heliospheric MeV and mostly cosmic ray > 70 MeV ions before V1 exited the Heliosphere. Explanation: the heliopause moved faster than V1, due to changes in the dynamical pressure of the solar wind. The cosmic ray count rate has not changed much in the subsequent 6 years.
Might something similar be happening to Voyager-2 right now?
Veteránok 2017 Energy spectra of protons and alpha particles inside and outside of the heliosphere: V2 was still inside (blue, power spectrum at low energies), while V2 outside (red).
Radial streaming velocity Plasma density x R^2 Log of plasma temperature
Several ambitious big projects have brought first results and are promising much more in the field of astroparticle physics. But one should not forget: microscopes might contribute to science as much as giant telescopes. Solar- heliospheric research continues to be very useful for understanding processes on larger and more energetic scales. The magnetosphere of Earth Jim Cronin and Alan Watson, fathers of PAO
Veteránok 2017 (CME: Coronal Mass Ejection, vagyis anyagkidobódás a napkoronából)
A Voyager-1 szonda élettartamát sikerült pár évvel meghosszabbítani a 37 éve be sem kapcsolt fúvókák újraindításával
Megismertük a külső bolygókat és holdjaikat, mágneses terüket. A bolygókon túli napszélben felfedeztük a nagy lökéshullámokat és a lelassult napszél jellemzőit, a helioszféra határtartományát. Először jutott ki űrszonda a csillagközi térbe, és adott hírt az ottani gáz és a nagyenergiájú részecskék jellemzőiről. Mint ahogy a Nap a csillagok megértését segíti, a helioszféra a csillagok környezetére ad hasznos mintát, a lökéshullámok pedig a kozmikus sugárzás keletkezésének megértésében segítenek.
Mi várható még?
Az energiellátás évente kb. 4 wattal csökken, a V1-nél 2021., a V2-nél már 2020. után egyes műszereket időnként le kell kapcsolni. 2025. után tudományos adatok már nem várhatók. De közeledünk a Nap aktivitási minimumához, és ekkor talán a V2 is átlépi a helioszféra határát, és méri a határtartomány és csillagközi gáz jellemzőit.
De legfőképpen: továbbra is várjuk a váratlan eseményeket!
Results of the International Boundary Explorer, detecting neutralized energetic solar wind ions returning again to the inner heliosphere. The Ibex ring might be caused by ion trapping in local interstellar magnetic structures.