In the novel The Three-Body Problem, does the Sun's amplification of radio transmissions have a scientific basis?

Question

Per Wikipedia

[...] However, she is rescued at the last minute by Yang Weining and Lei Zhicheng, two military physicists working under Red Coast (a Chinese initiative for alien communication similar to SETI) who require Ye's skills in physics. Ye discovers the possibility of amplifying outgoing radio messages by bouncing them off the sun and sends a message. Eight years later, by now in a loveless marriage with Yang, Ye receives a message from a concerned alien pacifist from the planet Trisolaris, warning her not to respond or else the inhabitants of Trisolaris will locate and invade Earth.

Does the novel go into any detail regarding the scientific basis behind this amplification?

Answer 1

As far as can be told, the 'solar mirror' phenomenon is a) normal within stars in this fictional universe and b) a purely fictional construct of the author.

There are literally pages of borderline pseudo-science about this, but the most obvious passage to describe the phenomenon of solar mirror reflectivity is below.

But now, Ye made the first step in confirming her guess about the gain reflectivity of solar energy mirrors: The energy mirrors not only reflected radiation coming from the lower-frequency side, but amplified it. All the mysterious sudden fluctuations within narrow frequency bands that she had observed were in fact the result of other radiation coming from space being amplified after reflecting off an energy mirror in the sun. That was why there were no observable disturbances on the surface of the sun. This time, after the Jovian radio outbursts reached the sun, they were re-emitted, as if by a mirror, after being amplified about a hundred million times. The Earth received both sets of emissions, before and after the amplification, separated by sixteen minutes and forty-two seconds.

The sun was an amplifier for radio waves.

However, there was a question: The sun must be receiving electromagnetic radiation from space every second, including radio waves emitted by the Earth. Why were only some of the waves amplified? The answer was simple: In addition to the selectivity of the energy mirrors for frequencies they would reflect, the main reason was the shielding effect of the solar convection zone. The endlessly boiling convection zone situated outside the radiation zone was the outermost liquid layer of the sun. The radio waves coming from space must first penetrate the convection zone to reach the energy mirrors in the radiation zone, where they would be amplified and reflected back out. This meant that in order to reach the energy mirrors, the waves would have to be more powerful than a threshold value. The vast majority of Earth-based radio sources could not cross this threshold, but the Jovian radio outburst did—

And Red Coast’s maximum transmission power also exceeded the threshold.

The problem with solar outages was not resolved, but another exciting possibility presented itself: Humans could use the sun as a superantenna, and, through it, broadcast radio waves to the universe. The radio waves would be sent with the power of the sun, hundreds of millions of times greater than the total usable transmission power on Earth.

Earth civilization had a way to transmit at the level of a Kardashev Type II civilization.

Answer 2

Liu did his homework to ensure his fictional universe is realistic so the novel could be enjoyed by physicists. There are three physics properties that theoretically make this possible:

1. total internal reflection HAM radio enthusiasts use it to bounce signals off the Earth's ionosphere
2. laser cavities or traveling wave tubes can occur in natural structures, like the layers of plasma in the sun
3. nonlinear optics: I've done experiments where something as simple as cuvet of tea can form self-focusing filaments of light (or radio) if the EM radiation heats the liquid in a nonuniform way

So yes, I think it's plausible, but don't know if our Sun's structure actually makes it possible.

Answer 3

There is real science on this!

Direct amplification of electromagnetic waves by beam-plasma instability and its application to solar type-III bursts

Abstract

When a weakly magnetized, relativistic electron beam is injected into a plasma, the beam-plasma instability excited by nonresonant wave-particle interaction can amplify directly the electromagnetic waves. Results of calculation show that, in regions far from resonance, electromagnetic waves can still be amplified over a wide frequency range, and form plateaus under each resonance peak. As the harmonic wave number increases, the peak value of the growth rate decreases and the width of the peak also diminishes. This paper analyzes how the growth rate varies with the background parameter , and the direction of incidence of the energetic electrons and the direction of the radiation. Under typical solar coronal conditions, the size, bandwidth, directivity, polarization and harmonic modes of the waves so amplified can be used to explain the solar type-III radio bursts. The present study can also apply to plasma emission in other astronomical bodies.