LOFAR Solar KSP Workshop II, APS, Potsdam, Germany, 24–25 June, 2009 Utilising radio OAM to study space plasma vorticity The LOIS concept and IBM software Bo Thidé Swedish Institute of Space Physics, IRF, and Uppsala University, Uppsala, Sweden LOIS Space Centre, Växjö, Sweden with contributions from the LOIS OAM/radio topology collaboration J. Bergman, S. Mohammadi, T. Leyser, E. Nordblad (Uppsala), L. Daldorff, (FMI, Helsinki), R. Karlsson (Graz), T. Carozzi (Glasgow), H. Lundstedt (Lund), W. Löwe, W. Baan, M. Milrad (Växjö), M. Fredriksson, R. Gustavsson, N. Ibragimov, R. Khamitova. C. Svahnberg (BTH, Karlskrona), H. Then (Oldenburg), T. Mendonca (Lisbon), Ya. N. Istomin (Lebedev Institute, Moscow), E. Weibust, B. Sjökvist (IBM Sweden), B. Elmegreen, L. Amini, A. Biem, D. Turaga, and O. Verscheure (IBM Research, NY)

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé2 Early LOFAR proposals – Birth of the LOIS project

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé3 LOIS idea: Optimize LOFAR for space weather, solar physics, ionospheric turbulence and calibration... Download from

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Fundamental question: How much physical information is embedded in EM radiation? Bo Thidé4 Symmetric under inhomogeneous Lorentz transformations. The concomitant Lie group is the 10-dimensional Poincaré group P(10). According to Noether’s theorem there therefore exist 10 conserved EM quantities. In fact there exist 23 exact continuous symmetries/conserved quantities (in vacuo), plus an as yet unknown number of approximate, conservation laws [Ibragimov, 2008]. Start from the beginning: the microscopic Maxwell-Lorentz equations

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Conserved quantities in EM fields and matter (1) Bo Thidé5 Homogeneity in time => conservation of system energy (Poynting’s theorem): Homogeneity in space => conservation of system linear momentum (gives, e.g., rise to EM Doppler shift):

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Conserved quantities in EM fields an matter (2) Bo Thidé6 Invariance under proper Lorentz transformations => conservation of system centre of energy: Isotropy in space => conservation of system angular momentum (gives rise to azimuthal Doppler shift): Foundation of ‘angular momentum radio’ and vorticity probing radio and radar methods.

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Total radiated EM field angular momentum Bo Thidé7 For radiation beams in free space, EM field angular momentum J em can be separated into two parts [Jackson, 1998; Thidé, 2009]: For each single Fourier mode in real-valued representation [van Enk & Nienhuis, 1992]: The first part is the EM spin angular momentum (SAM) S em, a.k.a. wave polarisation, and the second part is the EM orbital angular momentum (OAM) L em. NB: In general, both EM linear momentum p em, and EM angular momentum J em = L em + S em are radiated all the way out to the far zone!

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé8 That far-zone POAM is generated by near-zone longitudinal E fields is well known since 1914

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Micromechanical action of laser light carrying SAM and OAM Bo Thidé9 Spin angular momentum s = 1 Orbital angular momentum l = 8 Particles of sizes 1–3 μm irradiated by SAM/OAM laser beams

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 EM beams on same frequency but different OAM are orthogonal and do not interfere with each other! Bo Thidé10 M. J. Padgett, J. Leach et al., U. Glasgow, UK; Royal Society l=+1 l=+3 l= -4 Spiraling Poynting/OAM vectors carry a lot of information! The Jones matrix goes from 2×2 to 2(j+1)×2(j+1), j=s+l.

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé11 Topological degrees of freedom have revolutionised wireless communications

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 First observation of angular momentum in ionospheric radio emissions, Tromsø, 1983 Bo Thidé12 Bo Thidé. Stimulated Electromagnetic Emission and nonlinear wave-wave interactions in ionospheric heating experiments. In M. Q. Tran and M. L. Sawley, editors, Proceedings, Contributed Papers, International Conference on Plasma Physics, volume I, page 131, Lausanne, Switzerland, 27 June-3 July Centre de Recherche en Physique des Plasmas, Ecole Polytechnique Federal de Lausanne, CRPP-EPFL.Stimulated Electromagnetic Emission and nonlinear wave-wave interactions in ionospheric heating experiments O mode SEE X mode SEE Circular, (nearly) O-mode pumping

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Imparting OAM onto an EM beam (laser, mm wave) with the help of a spiral plate or hologram Bo Thidé13

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Observations at 94 GHz of angular momentum induced azimuthal (rotational ) Doppler shift Bo Thidé14

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé15 Use of photon orbital angular momentum (POAM) has come to the fore in astronomy and astrophysics

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé16 Europe is leading the way

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé17 Courtesy Paul Rodrigues Deep space radar requirements

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 OAM spectrum probing (spiral imaging) – a new scatter radar diagnostic Bo Thidé18 Recent digital spiral imaging experiments (Ll. Torner et al., Opt. Express, 13, 873–881, 2005; Molina-Terriza et al., J. Eur. Opt. Soc., Rapid Publ., 2, 07014, 2007) have demonstrated that probing with OAM gives a wealth of new information about the object under study. The stimulus…

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Spiral (OAM) spectrum imaging results Bo Thidé19 …and its response

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Linear transfer of OAM radio ↔ plasma Bo Thidé20 PRL, in press

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Nonlinear transfer of OAM radio plasma Bo Thidé21 Brillouin = ion line Raman = plasma line

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 First unambiguous observation of Stimulated Brillouin Scattering in the ionosphere Bo Thidé22

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé23 First OAM/vorticity radio injection experiment in the ionospheric plasma (HAARP, Alaska, 27 Feb, 2008)

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Field vector sensing means total configurability Bo Thidé24 Very good solar radio coronagraph!

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Radio beam topology degrees of freedom Linear momentum (Poynting) flux and E vs. OAM Bo Thidé25 Mohammadi et al., IEEE Trans. Ant. Prop., in press, 2009

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009BoThidé26 Radio beam topology degrees of freedom Left: Conventional linear momentum (Poynting) flux and E Right: Orbital angular momentum flux

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé27 LOIS has measured the photon spin current V in ionospheric radio signals since 2003

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé28 LOIS resources 2003–today (total ~ 2.5 MEur) Computer cluster (two SUR grants from IBM), currently in Uppsala. To be moved to Ronneby Radio Sweden’s 500 kW transmitter located about 100 km south of the Växjö LOIS test station and 100 km south-west of the Ronneby prototype station site. Will be used for space radar tests. The control room at the LOIS Test Station Risinge/Växjö. 9m×8m × 6m antenna chamber, Ångström Lab, Uppsala Magnetometer, LOIS Test Station, Risinge/Växjö

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé29 New LOIS prototype site at Angelskog, Ronneby Left photos taken 21 December, 2007, at 14:00 local time. Right photo from eniro.se

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 LOIS prototype station under construction in Ronneby To be augmented by two outer, concentric rings, with 16 and 32 radio units, respectively, for a total of 56 units with three dipoles each (funding permitting) Bo Thidé30

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé31 Use three orthogonal electric and magnetic antennas to sample the entire EM field vector New generation LOIS radio sensors, to be first used at EISCAT, autumn 2009

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, D vector antenna allows entirely new radio Better SNR, polarisation in real time, DOA,… Bo Thidé32 Click on pictures for animation! Real data from a real, live outdoor vector receiver at Ångström Lab in Uppsala. On line since Vector coherency gives superior SNR relative to conventional scalar intensity Instantaneous wave polarisation from one single vector antenna

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 LOIS prototype station sensitivity 48 tripoles=144 dipoles Bo Thidé33

Bo Thidé34 Swedish LOFAR Science Meeting, Stockholm, 15 January, D LOFAR/SKA-type interferometers may exhibit polarisation aberration. 3D interferometers do not

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé35 IBM InfoSphere Streams ideal for LOIS radio data

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé36 IBM InfoSphere Streams partly developed for LOIS

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé37 InfoSphere Streams (System S) program for a distributed network of LOIS radio sensors

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 LOIS software developed in collaboration with IBM Bo Thidé38

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé39 IBM’s latest major data stream software package developed for LOIS radio data

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 LOIS has given rise to articles in the press Bo Thidé40

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 LOIS /LOFAR on Discovery Channel? Bo Thidé41

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Thank you for your attention Bo Thidé42....there may be more things in heaven and earth than even Maxwell had dreamt of …

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé43 EM equivalent of fluid vorticity

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé44 Phase singularities (dislocations) are to be expected in radio beams propagating through space

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Standard textbooks show that classical EM angular momentum is indeed radiated all the way to infinity Bo Thidé45

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009Bo Thidé46 Pack EM beams with much more data by utilising more topological degrees of freedom

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Single photons can carry both spin angular momentum S and orbital angular momentum L! Bo Thidé47

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Hyperentangled SAM and OAM photon states break the linear-optics channel capacity threshold Bo Thidé48

LOFAR Solar SKP Workshop II, APS. Potsdam, Germany, 24–25 June, 2009 Shannon’s law revisited Bo Thidé49