English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Horizon-scale observations from the Event Horizon Telescope (EHT) haveenabled precision study of supermassive black hole accretion. Contemporaryaccretion modeling often treats the inflowing plasma as a single, thermalfluid, but microphysical kinetic effects can lead to significant deviationsfrom this idealized picture. We investigate how the helicity barrier influencesEHT-accessible electromagnetic observables by employing a simple model forelectron heating based on kinetic physics and the cascade of energy andhelicity in unbalanced turbulence. Although the helicity barrier plays only aminor role in regions with high plasma-beta, like in SANE disks, it maysubstantially impact in regions with more ordered magnetic fields, such as thejet and its surrounding wind in SANE flows as well as throughout the entiredomain in MAD flows. In SANE flows, emission shifts from the funnel walltowards the lower-magnetization disk region; in MAD flows the emissionmorphology remains largely unchanged. Including the helicity barrier leads tocharacteristically lower electron temperatures, and neglecting it can lead tounderestimated accretion rates and inferred jet powers. The correspondinghigher plasma densities result in increased depolarization and Faraday depthsthereby decreasing the amplitude of the beta_2 coefficient while leaving itsangle unchanged. Both the increased jet power and lower |beta_2| may helpalleviate outstanding tensions between modeling and EHT observations. We alsofind that the estimated ring diameter may be underestimated when the helicitybarrier is neglected. Our results underscore the significance of the helicitybarrier in shaping black hole observables and inferred accretion systemparameters.

Balanced Turbulence and the Helicity Barrier in Black Hole Accretion