DeepMind RL controller shapes TCV plasmas and sustains droplets

A deep RL controller commanding all 19 TCV coils produced and held elongated, negative-triangularity, snowflake and twin-droplet plasmas at EPFL's Swiss Plasma Center (Nature, 16 February 2022).

AI system

System

DeepMind deep reinforcement learning magnetic controller for TCV (MLP policy commanding 19 coils)

Model

Not assessed

Release

Not assessed

Application developer

DeepMind, with the Swiss Plasma Center, EPFL

Role

Not assessed

Configuration

Not assessed

Inputs and outputs

Not assessed

Autonomy

Not assessed

Workflow

A high-fidelity simulator (FGE) and equilibrium reconstruction (LIUQE) of the target tokamak available for training. A flexible research tokamak with 19 independently actuated coils. A real-time control system able to run a neural network policy at the required rate.

Human oversight

Not assessed

Relation to AI

The reinforcement learning policy directly issued the coil voltage commands during the discharges, so the configurations are its output. The evidence is the peer-reviewed paper by the maker (DeepMind) and the operator (EPFL) plus an independent news report quoting an outside expert. Developer and deployer collaborated on the paper.

AI contribution

The reinforcement learning policy directly issued the coil voltage commands during the discharges, so the configurations are its output. The evidence is the peer-reviewed paper by the maker (DeepMind) and the operator (EPFL) plus an independent news report quoting an outside expert. Developer and deployer collaborated on the paper.

Benefits

Outcome identifiers

Not assessed

Benefit

narrowed the separation to 6.6 cm with a combined RMSE of 3.7 cm

Category

Improved Task Accuracy

Status

Not assessed

Beneficiary groups

Organizations. Society.

Beneficiaries

Not assessed

Reach

Not assessed

Distribution and access

Not assessed

Duration

Not assessed

Expected?

Yes

Costs and harms

Not assessed

Measurement

Studies

Not assessed

Study design

Not assessed

Measurement

Not assessed

Setting and sample

Not assessed

Measures

narrowed the separation to 6.6 cm with a combined RMSE of 3.7 cm

Comparison

Not assessed

Results

narrowed the separation to 6.6 cm with a combined RMSE of 3.7 cm

Additional value from AI

Not assessed

Limitations

Not assessed

Denominators

Not assessed

Materials for replication

Not assessed

Money

Kind of value

Not assessed

Amount

Not assessed

Currency and prices

Not assessed

Period and unit

Not assessed

Realization

Not assessed

Recipients and payers

Not assessed

Gross or net

Not assessed

Included costs

Not assessed

Comparison

Not assessed

Method

Not assessed

Return and payback

Not assessed

People and places

Participants

Developer: DeepMind, with the Swiss Plasma Center, EPFL. Operator: Swiss Plasma Center, EPFL (TCV).

Jurisdictions

Benefit: Lausanne, Switzerland. Developer: United Kingdom. Operator: Switzerland.

Ownership and control

Not assessed

Dependencies

Not assessed

Cross-border connections

Not assessed

Geopolitical implications

Not assessed

Follow-up

Conditions for replication

A simulator accurate enough for zero-shot transfer to the device. Operator-specified targets within the device's physical and operational constraints. Access to machine time on a research tokamak.

Replication attempts

1 follow-up entries. Benefit recurred: 1.

Later findings

21 July 2023. DeepMind and the Swiss Plasma Center reported upgraded RL controllers with up to 65% better shape accuracy in simulation and new validating experiments on TCV.

Availability

Not assessed

Institutional decision

Not assessed

Grounds

Not assessed

Action and result

Not assessed

Success criterion

Not assessed

Evidence

Source numbers

AIBD-0164-source-0001–0004

Citations

Numbered references below.

Language

Not assessed

Source relationships

Developer, Independent

Original evidence

Not assessed

Access and versions

Not assessed

Supported findings

Not assessed

Evidence strength

Not assessed

Missing evidence

Not assessed

Grades

Assessed benefits

Organizations. Society.

Depth

Organizations: 3. Society: Not assessed.

Reasons

Organizations: The Swiss Plasma Center gained a controller the paper calls a notable advance for tokamak feedback control. It brought less design effort for new configurations and new droplet experiments. Society: No societal outcome beyond research progress is documented.

Observed or intended

Not assessed

Rubric

Not assessed

Assessor and date

Not assessed

Alternative assessments

Not assessed

Fill

Independently reported

Entry details

Kind

Not assessed

Field

Energy research (magnetic confinement fusion). Tokamak plasma control.

Purpose

The controller was built to shape and maintain plasmas in TCV from high-level objectives; the configurations produced, including droplets, were its intended use.

Dates

Date basis unassessed: 2022 (precision unassessed). Updated: 21 October 2026.

Stage

Not assessed

Version

SHA-256: 067f32980f20…

References

Other identifiers

Not assessed

Category mappings

Not assessed

Brief

Not assessed

Revisions

5 revisions. Latest: 21 October 2026.

Sources

  1. Peer-reviewed study Developer

    Degrave, J., Felici, F., Buchli, J. et al., 'Magnetic control of tokamak plasmas through deep reinforcement learning', Nature 602, 414–419 (2022), doi:10.1038/s41586-021-04301-9

  2. Preprint Developer

    Tracey, B. D., Michi, A., Chervonyi, Y., et al. (2023). Towards practical reinforcement learning for tokamak magnetic control. arXiv:2307.11546, 21 July 2023 (v2 5 October 2023).

  3. News report Independent author

    Will Douglas Heaven, 'DeepMind's AI can control superheated plasma inside a fusion reactor', MIT Technology Review, 16 February 2022