Quote:Toroidal electromagnetic pulses can be generated using a device known as a horn microwave antenna. This electromagnetic “vortex cannon” produces skyrmion topological structures that might be employed for information encoding or for probing the dynamics of light–matter interactions, according to its developers in China, Singapore and the UK.

Examples of toroidal or doughnut-like topology abound in physics – in objects such as Mobius strips and Klein bottles, for example. It is also seen in simpler structures like smoke rings in air and vortex rings in water, as well as in nuclear currents. Until now, however, no one had succeeded in directly generating this topology in electromagnetic waves.

Quote:Topological electromagnetic fields exhibit vast potential applications in information and energy transmission12,13,14,15,16,17,18 and super-resolution metrology or microscopy19,20,21,22,23,24, thereby offering a potential avenue for achieving precise 3D positioning based on a single transmission antenna in free space. In 1996, Hellwarth and Nouchi introduced toroidal pulses, an exact solution to Maxwell’s equations25, which possess complex non-transverse skyrmion topological structures26,27,28,29, space-time nonseparability 30,31,32,33, and strong interactions with matter34,35. Recently, electromagnetic toroidal pulses have been successfully generated in the optics, terahertz, and microwave36,37,38, laying the foundation for their practical applications. However, to the best of our knowledge, there have been no reports of successful experimental implementations of toroidal pulses until now.

Quote:Recent developments in nanophotonics and structured light have led to the creation of similar topological particle-like textures in optical fields, known as optical skyrmions. In contrast to topological spin textures embedded in matter, optical skyrmions can propagate in free space, enabling long-distance information transfer. Creating and controlling free-space topological textures with structured light is an emerging field that will drive conceptual revolutions from solid-state data storage to dynamic long-range information transfer

Quote:The flow over a delta wing at high angles of attack is characterized by the presence of two large-scale primary vortices on the leeward side of the wing. These vortices contribute substantially to lift production at high angles of attack. Therefore, vortex breakdown, which can be induced by unfavorable pressure gradients or freestream disturbances,...

Quote:The B-2 had already shown its ability to fly halfway around the world and back—a 37-hour, 29,000-nautical-mile return flight from Whiteman Air Force Base, Missouri, to Guam in the Pacific with several air-to-air refuelings en route. With gravity shielding—if such a thing could be moved from the laboratory to a fully fledged aircraft program— either its range could be extended or the number of midair refuelings cut. Either of these would make the technology a powerful draw

Quote:LaViolette had written an elegant thesis about the B-2 and its antigravitational properties soon after the publication of a revelatory article
in Aviation Week, the "bible" of the U.S. aerospace industry, in which
a number of black-world engineers had whistle-blown to the author,
the magazine's West Coast editor, Bill Scott, about a host of amazing
new technologies supposedly being developed in the deeply classified
environment. One of these related to "electrostatic field-generating
techniques" in the B-2's wing leading edge with a view to reducing the
giant Stealth Bomber's radar cross section.

Quote:42.65.Jx; 42.68.Bz; 64.70.Hz; Beam trapping self-focusing and defocusing; self-phase modulation; Atmospheric turbulence effects; Solid-vapor transitions

Laser-filament-induced snow formation in a subsaturated zone in a cloud chamber: Experimental and theoretical study

Quote:1 kHz, 2 mJ, 45 fs, 800 nm laser pulses were fired into a laboratory diffusion cloud chamber through a subsaturated zone (relative humidity ∼73%, T ∼ 4.3 °C). After 60 min of laser irradiation, an oval-shaped snow pile was observed right below the filament center and weighed ∼12.0 mg. The air current velocity at the edge of the vortices was estimated to be ∼16.5 cm/s. Scattering scenes recorded from the side show that filament-induced turbulence were formed inside the cloud chamber with two vortices below the filament

Quote:Keywords
Laser, Filamentation, Air Lasing, Laser Induced Breakdown Spectroscopy (LIBS), Laser Induced Discharge, Ultrashort Pulse Lasers, Nonlinear Optics

Sponsors
Department of Energy (DOE), Airforce Research Lab (AFRL), Army Research Office (ARO)


Abstract

Laser filamentation is a fascinating phenomenon that occurs when an intense laser beam travels through transparent materials, in particular air. At sufficiently high power (TW in the near IR, GW in the UV), instead of spreading out like a regular laser beam, something remarkable happens: the laser beam becomes tightly focused, creating a thin and intense column of light called a laser filament.

Quote:Femtosecond laser pulses could form self-guided filaments in air. It is well known that a femtosecond filamentation arises from a dynamic balance between Kerr self-focusing and self-generated plasma defocusing and/or negative higher-order Kerr terms[1–6]. In recent years, femtosecond filamentation has attracted much attention because of its potential applications, such as in pollutant detection[1,7], lightning control[8,9], laser-assisted water nucleation and snow formation[10–14], and fluid dynamic measurements[15,16], etc.

Quote:This Electrolaser experiment was demonstrated 
on a smaller scale by the US Army in the mid  2000s to create plasma filaments close to a near 
by target and then send a high power electrical  discharge down the filaments to connect with it, 
be that an object or person. However, it now  seems that an experiment in this field which 
was known as the Phoenix project, where the U.S.  Navy tested an electro-laser against aircraft and 

missiles in 1985 and this was part of President  Regans SDI or Strategic Defense Initiative.

• Electromagnetic pulses with toroidal (ring-like) field structures that have recently been generated in the lab. (rogue-nation.com)
  
• Research on topological electromagnetic fields involving skyrmion-like structures and space-time nonseparability. (rogue-nation.com)
  
• The possibility of electric-dominant and magnetic-dominant skyrmion modes within these toroidal pulses. (rogue-nation.com)
  

• you see loops (ring shadows),
  
• you see radial expansion (cross-section fields),
  
• you see twist patterns that cannot be reduced to simple divergence or curl alone.
  

• the fields possess a topological linkage (the field lines wrap around each other),
  
• the pulse itself has a space-time nonseparable structure, meaning how the fields evolve depends on how space and time are “sliced” in the lab frame. (rogue-nation.com)
  

• the fields can form patterns that cannot be “unknotted” without breaking continuity,
  
• electric and magnetic parts can form linked structures that are intertwined. (rogue-nation.com)
  

• electric-dominant skyrmion modes, and
  
• magnetic-dominant skyrmion modes within the same overall field configuration. (rogue-nation.com)
  

• A higher-dimensional field structure (the underlying toroidal/skyrmion configuration) exists as a coherent whole.
  
• What we call “electric” or “magnetic” behavior in experiments is a slice or shadow of this deeper structure under a particular observational orientation.
  
• The observed switching or dominance of one component over another is not separate forces appearing, but different projections of the same invariant field geometry.
  

Quote:Toroidal electromagnetic pulses are real examples where electric and magnetic field patterns cannot be simply separated, because they are inseparable shadows of a single topologically structured field. (rogue-nation.com)

• constrains the geometry
  
• hides the internal structure
  
• forces a static projection
  

• is unconstrained
  
• self-organizes
  
• reveals topology dynamically
  

• toroids
  
• vortices
  
• helices
  
• filament chains
  

• rotations are smoother in higher dimension
  
• 3D projections look fragmented
  
• components swap continuously
  

• the higher-dimensional motion is smooth
  
• the 3D manifestation fractures into patterns
  
• loops and lines trade dominance
  

Quote:High-intensity lasers force the electromagnetic projection to reveal its hidden rotational and topological structure, producing filaments, vortices, and toroids as stable shadows of a higher-dimensional object.

Quote:Two pairs of Helmholtz coils placed at right angles are known to be the simplest configuration for uniform field generation but the space available around the sample stage dictates that the coil pair is slightly further apart than that of a Helmholtz configuration (see Supplementary Information Figure S1 for details of the coil holder design). This introduces small non-uniformity into the field, which is discussed later.