Press release:
https://www.nasa.gov/feature/goddard/2017/nasas-van-allen-probes-spot-man-made-barrier-shrouding-earth

“A number of experiments and observations have figured out that, under the right conditions, radio communications signals in the VLF frequency range can in fact affect the properties of the high-energy radiation environment around the Earth,” said Phil Erickson, assistant director at the MIT Haystack Observatory, Westford, Massachusetts.

VLF signals are transmitted from ground stations at huge powers to communicate with submarines deep in the ocean. While these waves are intended for communications below the surface, they also extend out beyond our atmosphere, shrouding Earth in a VLF bubble. This bubble is even seen by spacecraft high above Earth’s surface, such as NASA’s Van Allen Probes, which study electrons and ions in the near-Earth environment.

The probes have noticed an interesting coincidence — the outward extent of the VLF bubble corresponds almost exactly to the inner edge of the Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields. Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, coined this lower limit the “impenetrable barrier” and speculates that if there were no human VLF transmissions, the boundary would likely stretch closer to Earth. Indeed, comparisons of the modern extent of the radiation belts from Van Allen Probe data show the inner boundary to be much farther away than its recorded position in satellite data from the 1960s, when VLF transmissions were more limited.

With further study, VLF transmissions may serve as a way to remove excess radiation from the near-Earth environment. Plans are already underway to test VLF transmissions in the upper atmosphere to see if they could remove excess charged particles — which can appear during periods of intense space weather, such as when the sun erupts with giant clouds of particles and energy.

The original paper is here:
https://link.springer.com/article/10.1007/s11214-017-0357-5
but will cost $39.95 unless you have a subscription...

I scanned the paper- the bulk of the paper talks about the impact of High altitude nuclear testing on space weather and EMP effects on the ground. Section 8 talks about the VLF interactions with space weather - and lays out the observations of that effect... its not clear that they are really claiming that current VLF emissions ARE significantly modifying the location of the Van Allen belt- just that they could and further study is being conducted. SOME effect is observed but it isnt conclusively proven the existing VLF emissions are pushing the belts out.
One interesting quote from the paper:

For example, the US Air Force DSX satellite scheduled for a 2017 launch will carry an onboard VLF transmitter for in-situ attempts to initiate radiation belt remediation mechanisms

Publicly available paper on this satellite is here:
lws-set.gsfc.nasa.gov/documents/dsx_paper.pdf

Wave Particle Interaction Experiment:
Researching the physics of very low-frequency
(VLF) transmissions in the magnetosphere and
characterizing the feasibility of natural and
man-made VLF waves to reduce space
radiation;

I read about the 'metal needles' you talk about when I worked at MIT-Lincoln Lab, (They did that project-called West Ford)you can find more on that here:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwjR6o-l0_rTAhXIVyYKHUOFCHcQFggsMAE&url=https%3A%2F%2Fwww.ll.mit.edu%2Fpublications%2Flabnotes%2FLooking_Back_3.pdf&usg=AFQjCNGUnRpaVaOxaIMKvxpgcYedH_UUOw&cad=rja
and here:
https://en.wikipedia.org/wiki/Project_West_Ford
Some are still up there...