Not tDCS. It looks like TMS (Transcranial Magnetic Stimulation) but I’ve not heard of TMS being applied for more than short bursts before. Also of note in the article is the description of their target:

Their training programme targets the brain’s ‘dorsal attention network’, which links regions of the prefrontal cortex – the bit of the brain above the eyes that helps us make decisions – and the parietal cortex, the ‘switchboard’ for our senses, which is above and slightly behind the ears.

(Caroline Williams)The pulses were aimed at my left prefrontal lobe, to dampen the activity there (Caroline Williams)When I get to the stimulation the next day, it’s not as bad as I feared. At least not at first. For the first minute or so it feels a bit like popping candy is going off under my skull. Five minutes in, though, and it’s seriously annoying – like the worst school bully ever repeatedly flicking me on the head.In all, I have two eight-minute-long sessions of magnetic stimulation, each followed by a 12-minute-long session of computer-based training. I also do three 12-minute blocks of training twice a day, over the internet, wherever my laptop and I happen to be.

Source: BBC – Future – Concentrate! How to tame a wandering mind