High Priority Objectives

Successfully design and produce a single style of the carbon ablation rod by the experimental date (late April).

Second Priority Objectives

Design multiple rods to probe different ablative scenarios, such as blunt, curved, and concave rod head shapes.

WOW Design Solution

Get other relevant materials approved for use in the DiMES port such as silicon carbide (SiC).

Other Constraints

Designs must be approved by the General Atomics design review committee before being allowed into DIII-D.

Carbon Materials for Rod: Selection and Criteria

• • • Uniform Properties – The material is uniform throughout – Consistent Ablation

    • Acceptable Inside Tokamak–Ablated material must not contaminate above threshold level

    • Material has been used in the Tokamak before

Designing Rods with Geometric Variations & within Constraints

• Integrating rods into DiMES port dimensions.

  • • 2 cm^3 max volume exposed.

    • 1.5 cm max height of extruded portion.

• Design geometric variation of rods for different ablation regimes.

  • • A. Blunt

    • B. Hyper-sonic

    • C. Concave

Thermal Analysis is Needed for the Ablation Rod

• Thermal Stress Analysis on Ansys

  • • To estimate the heat stress on the rod

    • To ensure the rod facing plasma won’t ablate completely in 4 seconds

    • Not causing crack on the DiMES port due to the expansion of the rod

• Source of Heat stress on the Rod

  • • Condition is the main source due to the high heat flux facing the rod

    • Considering worst case scenario, conduction through the Dimes, and radiation throughout the entire Dimes Setup

Thermal analysis completed - March 24,2021

Current induced stress analysis completed - March 28,2021

Passed General Atomics design review - April 2,2021

Rod’s geometry finalized - April 4, 2021

Rods manufactured and produced - April 10,2021 to April 16,2021

First day of experiment - April 23,2021

Second day of experiment - April 27,2021

IMECE paper submitted - April 29,2021