# Learner lab record: Plasma regime and gain-chain map

Course: Plasma and fusion systems

Name: ____________________  Date: ____________________  Group: ____________________

## Investigation question

Which dimensionless and length-scale comparisons determine the valid plasma model, and where does fusion gain enter the full facility ledger?

## Setup

Use the plasma-regime laboratory. Establish density, temperature, field, and device size, compare characteristic scales, then trace fusion power through plasma, engineering, and electric gain definitions.

## Variables

| Variable | Role | Unit |
| --- | --- | --- |
| Density and temperature | plasma inputs | m⁻³ and eV |
| Magnetic field and device size | confinement inputs | T and m |
| Debye length, gyroradius, plasma frequency | dependent scales | m and Hz |
| Plasma/engineering/electric gain | system diagnostics | dimensionless |

## Predict before changing controls

1. Predict how increasing density changes Debye length and plasma frequency.

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2. Predict whether plasma gain above one guarantees net electric output.

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## Observation table

| density | temperature | B | Debye length | gyroradius | size ratio | Q plasma | Q electric |
| --- | --- | --- | --- | --- | --- | --- | --- |
|   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |

## Analyze

1. Which scale comparison supports a fluid description?

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2. Is the plasma magnetized for the selected species?

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3. Which gain definition excludes recirculating plant power?

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4. What instability or transport effect is outside this zero-dimensional model?

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## Evidence-bounded conclusion

For n=___, T=___, and B=___, the regime is ___ because ___; Qplasma=___ corresponds to net-electric status ___ after ___.

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