Celestial bodies, such as neutrons, or collapsed stars, called magnetars (magnetars), are enclosed in strong magnetic fields, presenting well-defined magnetic storms in space. According to quantum electrodynamics (QED) theory, these magnetic fields are so strong that they transform the vacuum of space into exotic plasmas of matter and antimatter in the form of pairs of negatively charged electrons and positively charged positrons . The emission of these pairs is thought to be responsible for the powerful FRBs.
paired plasma
Matter-antimatter plasmas, known as “pairon plasmas,” contrast with the usual plasmas, which fuel nuclear fusion reactions and make up 99 percent of the visible universe. This plasma consists only of electrons and much more massive matter in the form of nuclei or ions. Electron-positron plasmas consist of particles of equal mass but opposite charges that are annihilated and created. Such plasmas can exhibit quite different collective behavior.
“Our laboratory simulation is a small-scale simulation of the environment of a magnetar. This allows us to analyze the effect of QED on plasmas,” said Kenan Qu, a physicist in Princeton’s Department of Astrophysics. is the first author of a study presented as Science Highlights in , and the first author of a paper in Physical Review Letters, which is described in this paper.
Physicist Kenan Qu with images of FRBs in two galaxies. The top and bottom photos on the left show the galaxy, and the right is a digitally enhanced photo. Dotted ellipses mark outburst locations in the galaxy.
“Instead of simulating a strong magnetic field, we use a strong laser,” Qu said. “It converts energy into a pair of plasmons through a so-called QED cascade. The pair of plasmons then transfers the laser pulse to a higher frequency. This exciting result demonstrates the creation and observation of QED pairs of plasmons in the laboratory. prospects and enable experiments to test theories about fast radio bursts.”
Physicist Nat Fisch, professor of astrophysical sciences at Princeton University, associate director of academic affairs at PPPL, and the study’s principal investigator, noted that the lab-produced pair of plasmas had been created before. “And we think we know what laws govern their collective behavior. But until we actually generate a pair of plasmas in the lab that exhibit collective phenomena that we can detect, we won’t be absolutely sure of that.
collective behavior
He added: “The problem is that the collective behavior of paired plasmas is notoriously difficult to observe. An important step for us is to treat this as a joint production-observation problem, recognizing that a great observation method relaxes the conditions under which it must be produced. , and in turn lead us to a more practical facility.”
The unique simulations presented in the paper create high-density QED-pair plasmas by colliding a laser with a dense beam of electrons traveling close to the speed of light. This method is cost-effective compared to the commonly proposed method of colliding ultra-intense lasers to create QED cascades. The method also slows the motion of plasma particles, allowing for stronger collective effects.
“There are no lasers powerful enough to achieve this today, and it could cost billions of dollars to build them,” Qu said. Our approach strongly supports the use of an electron beam accelerator and a moderate-intensity laser to achieve QED on plasmas. We The implication of the research is that supporting this approach can lead to significant savings.”
“We are currently preparing to test the simulation with a new wave of laser and electron experiments at SLAC,” said SLAC researcher Sebastian Meuren, a former postdoctoral visiting scholar at Princeton University. “In a sense, what we are doing here is generating a radio burst. The beginning of the cascade.”
Evolving Experiment
“It would be very exciting if we could observe something like a radio burst in the laboratory,” Meuren said. “But the first part is just looking at the scattering of the electron beam, and once we do that, we’ll increase the laser intensity.” , to get to higher densities to really see electron-positron pairs. The idea is that the experiment will evolve over the next two years or so.”
The overall goal of this research is to understand how celestial bodies like magnetars create paired plasmas, and what the new physics associated with FRBs brings, this joint work was approved by the US National Nuclear Security Administration (NNSA). Supported by a grant awarded by the Department of Astrophysical Sciences to Princeton University and a grant awarded by the Department of Energy to Stanford University.
