This is a progression from my first question, here
(if this is too similar to my original question, please let me know of a better way to address this, as I am not getting the answers I need on that first question to be able to answer this one, and they seem separate enough to me.)
As with my first question, I found many questions and answers on this site that have related information, but don't directly answer my specific question. And I seem to be finding incomplete, incorrect, or conflicting information. Most specifically, this was prompted by a comment about Io being a major factor in Jupiter's radiation belt, and I attempted to research along those lines, but failed to find the information I needed, hence this new question. See these:
Conditions for human life in a Jupiter-like system
Captured Earth-Like Moons around Gas Giants
Naturally making a gas giant moon habitable
Calculating Radiation Zones of Gas Giants and the Effects on Its Moons?
Some of my research seems indicate that gas giant radiation comes almost exclusively from the planet itself. Others indicate that it's mainly a function of material contributed by orbiting bodies like Io. And nowhere did I find any attempt to balance it like I want to. So here's the actual question:
Is there a distance between the planet and the moon where the moon is far enough from the planet that the radiation from the Planet will not be able to get to the moon's surface in any quantity that is detrimental to human life, while at the same time the moon is close enough to the Planet so that the planet's magnetosphere is still providing the same level of radiation protection from the star's radiation as Earth's magnetosphere provides to Earth?
In other words, is there a gap between the lethal levels of radiation from the star and the lethal levels of radiation from the planet, and could a moon orbit the planet in that gap?
If such a gap is possible, what 'type' of Gas Giant is needed to create it?
Limitations:
Assume that the distance from the star is appropriate for life in this system, (in the Goldilocks zone, adjusted appropriately for a moon instead of a planet, etc.)
Assume the life on the moon is Earth life, disregard how it got there
Assume the moon has all necessary life supporting functions, including the same level of radiation defense as Earth's atmosphere, with the sole exception of it not having any magnetosphere of its own.
Assume no other moons or rings orbiting the Gas Giant are contributing anything that could significantly affect radiation levels in the system, the only radiation considerations are the star and the gas giant itself.
Disregard the reason for the missing magnetosphere on what is essentially Earth orbiting a gas giant in all other life support related aspects. though the moon does not need to be the same size, mass, density, etc., as Earth, if such adjustments are needed to allow a change in the orbital distance from the gas giant to put it in the gap in the radiation, and such changes can be 'hand-waved' to have no impact on the other life support functions of the planet.
The Gas Giant can be of any size/composition/configuration that current scientific understanding deems could plausibly exist, and that any layman could reasonably accurately label as a 'gas giant', regardless of accepted scientific definitions and terminology (including brown dwarf, ice giant, etc.) but that a layman would not even accidentally believe is a star or rocky planet.
Desired information:
Is there any Gas Giant that could have such a small/weak radiation belt system, and a large/strong enough magnetosphere at the same time, to produce such a gap?
Is the gap appropriately shaped (distortion due to stellar wind) that a moon could make a complete orbit of the planet without leaving the gap?
If the answer to the above is affirmative, what is the Gas Giant like (mass, volume, density, composition)? or is this something that most gas giant could have, and the ones without such a gap are the exceptions, and not the rule?
