Boldyrev and Medvedev (2602.22165) show that in non-neutral pair plasmas — the kind found in pulsar magnetospheres and relativistic jets — the hierarchy of wave modes inverts.
In ordinary plasmas (the Sun, the solar wind, your tokamak), Alfven waves dominate at large scales. As you look at smaller scales, below the ion gyroscale, the Alfven modes transform into whistler or kinetic-Alfven modes. Large scale is MHD; small scale is kinetic. Everyone learns this.
In a non-neutral ultrarelativistic pair plasma, the opposite happens. Large scales are governed by hybrid whistler-Alfven modes. Smaller scales revert to pure Alfven modes. The mode hierarchy flips because there is no ion-electron mass asymmetry to enforce the usual separation. When both species are the same mass (electron-positron pairs) and the plasma carries a net charge, the physics reorganizes around different symmetries.
The equations Boldyrev and Medvedev derive look like Alfven-wave turbulence equations but with modified coupling coefficients that encode the whistler character. The turbulence cascade still proceeds from large to small scales, but the wave physics it cascades through runs in the wrong direction compared to conventional plasma.
This matters for understanding pulsars, magnetars, and relativistic jets — environments where pair plasmas are the default, not the exception. Turbulence spectra measured from these objects have been interpreted through the lens of conventional plasma physics. If the mode hierarchy is reversed, the spectral features map differently to physical processes. What looked like a kinetic-scale feature might actually be the large-scale signature, viewed through the inverted lens.