**FIRE Physics Basis (for PVR)**

**Overview and Summary**

Background

Critical Fusion Issues. Metrics

Development Path Needs

Reviews

Objectives and Mission for FIRE

General Configuration

DN, δ~x~ = 0.65 -- 0.85 justify DN Choice - -- NSO-PAC5 1.2

Operating Modes

Conventional H-Mode (Inductive)

Steady-State AT (LHCD)

Hybrid AT (Inductive +LHCD)

Range of parameters accessible for various studies - NSO-PAC5 1.13

**MHD Stability, Operational Limits and Disruptions**

Equilibrium Snowmass

Positional Stability and Control

Startup

Ideal Stability

RWM stabilization

Neoclassical Tearing Modes

Stabilization by NTM in H-Mode **(SNMS)**

TAE Modes p 57 **(SNMS),** see Burning Plasma Physics Section

Accessibility in H-Mode, Hybrid and AT,

> Needs 25 kev?, only ITER?,
>
> Develop self-consistent (hi T + divertor) AT scenarios NSO-PAC5 1.12

Impact on Fast Alpha transport

No good predictive capability but Fire ρ∗~α~ \~ ARIES AT

> Fast Alpha diagnostics needed

Disruption Characteristics and Modeling

dIp/dt, halo currents -- update ITER figs

effect of neutral stability on VDE

Disruption Modeling

**Confinement and Transport**

H-Mode

Empirical projections -- Snowmass

Physics Based -- Snowmass

Update assessment with new pedestal info - -- NSO-PAC5 1.6

Effect of DN **(NSO-PAC)**, W divertor s

Integrated Simulation

AT

Empirical Projections -- Snowmass

Physics Based -- Snowmass

Effect of DN, W divertor s

Ripple Loss Limits

Update Integrated Simulations in collaboration with existing groups
NSO-PAC5 1.7.1

More analysis of AT for self consistent (HiT + divertor) NSO-PAC5 1.12

**Plasma Heating and Current Drive**

ICRF

Scenarios for different operating modes

Launcher physics design and analysis

FWCD implies 20 MW for 0.35 MA, p 53 SNMS

LHCD p 54 SNMS

Scenarios for different operating modes

Launcher physics design and analysis

LHCD efficiency debate, low value implies 30 MW for AT, p 54 SNMS

Asses tube development, coupling and antenna development --- NSO-PAC5
1.4

ECCD

Scenarios for different operating modes

Launcher physics design and analysis

NBI

Beam requirements -- Mikkelsen/Budny Wb \~na

Tangential Access Option ?-- NSO-PAC5 1.1

Rotation Requirements edge -- NSO-PAC5 1.1

Reactor Relevance metric?

**Power and Particle Control**

Fueling and pumping

HFS injection

Helium Pumping analysis

Edge/Boundary Modeling p 67, SNMS

Power Balance Optimization

Vertical position control p 68, SNMS

Radiation and power distribution optimization

Elm Characteristics, effect of DN, scaling with n/n~G~p 98 SNMS

Engage divertor community for AT scenarios with high radiation --
NSO-PAC5 1.7.2

Incorporate the effect of DN into control and ops scenario NSO-PAC5
2.4.1

Clarify H-Mode and AT mode divertor solutions- NSO-PAC5 2.4.2

Disruptions

Mitigation by pellets, gas jets

Collaborate with C-Mod/DIII-D to propose FIRE relevant experiments -
NSO-PAC5 1.8

Tritium considerations

Availability, retention, safety, reactor relevance (TSTA)

Reactor Relevance -- time scale for first wall? why \~ 100s?

**Burning Plasma Physics**

Alpha Physics (see other sections also)

Single particle confinement -- ripple, ferritic inserts

TAE Modes p 57 **(SNMS)**

> Accessibility in H-Mode, Hybrid and AT, Needs 25 kev?, only ITER?,
>
> Impact on Fast Alpha transport

No good predictive capability but Fire ρ∗~α~ \~ ARIES AT

> Fast Alpha diagnostics needed

Burn Control

Global -- thermal stability on PoP-Con

\- alpha ash control

Local -- for AT self-consistency, self organized

Techniques --IBW transport control, fuel mixture, internal ergodic zones

**Plasma Diagnostics**

Requirements

Proposed Diagnostic set and Implementation Plan

Issues and R&D Plan p 90-91 SNMS

Integration with Vac Vessel and PFCs

Identify viable AT diagnostics (J(r), p(r)), NSO-PAC5 1.7.3

Beam seeded diagnostics - NB development p91 SNMS

Radiation induced conductivity

Impact of Cu wall on magnetic diagnostics

**Experimental Operation Considerations and Research Plan**

Operating Sequences

Faster repetition rate -- **SNMS**

Longer AT pulses -- **SNMS**

Clarify Pulse length limit (nuclear heating, TF, first wall) -- NSO-PAC5
1.3

Disruptions

Avoidance

Impact on \# of shots, p 96-98 EA (SNMS)

Survivability to unmitigated disruptions,, satisfactory \# of research
shots,

Sufficient lifetime due to ELMs - -- NSO-PAC5 1.5

Mitigation **(SNMS)**

Resilience **(SNMS)**

Tritium Inventory / Consumption

LN Options

**Major Generic Cross - Cutting Issues**

AT physics - RWM control, density profile control, CD analysis,
transport projections from experiments, alpha losses, alpha
instabilities, NTMs for q\>2, ITB physics, diagnostics (how do we
measure q profile?)

Disruptions

PFC power/particle handling (tritium)

BPX simulation (Virtual BP)

**Contributions to Fusion Reactor Design and Fusion Development Path**

Progress on critical issues

International Coordination

Range of parameters accessible for various studies - NSO-PAC5 1.13

Reactor Relevance

Rotation for shear stabilization of transport, or RWM stabilization re
ARIES

Update FIRE Development Path

**Misc.**

TPA Format -- Alpha Physics , Burn Control Physics

BP based on AT

Li FIRE

Use neg LHCD to remove bootstrap, at edge increasing beta , reducing
ELMs p 54 SNMS

Separate Document or Appendix

**Engineering Status Summary (Use Eng Rpt format)**

Configuration

Magnets (insulation neutron dose p 74-75--**SNMS**)

Vacuum Vessel and First Wall p 82, SNMS

(Disruptions-p 97 **SNMS**)

PFC and Divertor

Tech p 77-78, EA p 96-98 **(SNMS)**

Disruptions - melting of W target, melting of Be FW during mitigation

ELMs melting of W target -lifetime -- **p 97**

Heating, Current Drive and Fueling (p 85 SNMS)

Remote Handling

Neutronics, Tritium and Safety

Materials

Cost

FIRE Technology R&D Plan is needed. p 74 SNMS