Skip to content
RichseenAtlas← AtlasSign in

Fusion triple product (n·T·τ_E)

node

The triple product is the plasma density n multiplied by the ion temperature T multiplied by the energy confinement time τ_E, and it is the single number that expresses why fusion is hard: all three quantities must be high at the same time, and improving one usually degrades another. It is conventionally expressed in units of keV·s·m⁻³. For a self-sustaining deuterium-tritium burn the threshold is commonly quoted at roughly 3×10²¹ keV·s·m⁻³, though published values range up to about 5–6×10²¹ depending on which criterion is being applied, what profile shapes are assumed, and whether ignition or merely breakeven is the target. The magnetic and inertial approaches attack the same product from opposite ends — seconds at 10²⁰ m⁻³ versus fractions of a nanosecond at some 10³¹ m⁻³ — which is why their results are not directly comparable.

A node is not a place. Drawing it on a map would assert something about the world that no stored fact supports.

Read in · 1

Evidence · 2
Timeline

No dated observations are stored for this object. Atlas shows what was observed and when — it does not infer a history.

Connections · 2
Assembled narrative · 1

Assembled from 23 blocks · 2 evidence · 22 related

  1. Story
  2. The triple product is the plasma density n multiplied by the ion temperature T multiplied by the energy confinement time τ_E, and it is the single number that expresses why fusion is hard: all three quantities must be high at the same time, and improving one usually degrades another. It is conventionally expressed in units of keV·s·m⁻³. For a self-sustaining deuterium-tritium burn the threshold is commonly quoted at roughly 3×10²¹ keV·s·m⁻³, though published values range up to about 5–6×10²¹ depending on which criterion is being applied, what profile shapes are assumed, and whether ignition or merely breakeven is the target. The magnetic and inertial approaches attack the same product from opposite ends — seconds at 10²⁰ m⁻³ versus fractions of a nanosecond at some 10³¹ m⁻³ — which is why their results are not directly comparable.
  3. Knowledge
  4. Wendelstein 7-X
  5. Fusion triple product (n·T·τ_E)
  6. Lawson criterion
  7. Connections
  8. Tokamak (toroidal magnetic confinement)
  9. Inertial confinement fusion
  10. Wendelstein 7-X
  11. Lawson criterion
  12. NIF exceeds the Lawson criterion for ignition
  13. EAST sustains a high-confinement plasma for 1,066 seconds
  14. Wendelstein 7-X sets a triple product record for long-duration plasmas
  15. Stellarator
  16. Fusion triple product (n·T·τ_E)
  17. Wendelstein 7-X sets a triple product record for long-duration plasmas
  18. Fusion triple product (n·T·τ_E)
  19. NIF exceeds the Lawson criterion for ignition
  20. NIF achieves target gain greater than unity for the first time
  21. Evidence
  22. The 8 August 2021 NIF shot produced about 1.35 MJ of fusion yield and exceeded the Lawson criterion for ignition without reaching target gain above unity
  23. An optimised stellarator has matched or exceeded tokamak triple-product values for long-duration plasmas, establishing magnetic confinement as more than one design lineage
Close the narrative
Observed changes · 0

No public Signals are attached to this object. Signals show what changed and when it was observed — never a direction or a rank.

Actions

Read the assembled narrativeContinue in StudioOpen TwinTwin does not start a decision from this kind of object.ShareSaveSaved objects are part of the authenticated projection, which is declared and not yet built.

/atlas?object=CONDITION_TRIPLE_PRODUCT&experience=CONDITION_TRIPLE_PRODUCT