# Simulating multi-stage magma intrusion in ASPECT: How to dynamically update T & composition in specific spacetime domains? **URL:** \ **Category:** ASPECT\ **Created:** [March 6, 2025, 5:21pm UTC](https://community.geodynamics.org/t/simulating-multi-stage-magma-intrusion-in-aspect-how-to-dynamically-update-t-composition-in-specific-spacetime-domains/3990 "2025-03-06T17:21:18Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![jbnaliboff](https://avatars.discourse-cdn.com/v4/letter/j/58956e/32.png) [@jbnaliboff](https://community.geodynamics.org/u/jbnaliboff)\ **Post date:** [March 21, 2025, 4:19pm UTC](https://community.geodynamics.org/t/simulating-multi-stage-magma-intrusion-in-aspect-how-to-dynamically-update-t-composition-in-specific-spacetime-domains/3990/2 "2025-03-21T16:19:12Z")
Hi @3Faker3, If I understand correctly, you would like to modify ASPECT’s internal solution (temperature, composition) at various points in time. There are ways to to this, and the [prescribed velocity cookbook](https://github.com/geodynamics/aspect/tree/main/cookbooks/prescribed_velocity) shows how define to prescribe internal velocities for a subduction corner flow problem. This approach can be applied to temperature and composition fields, and be adapted to have temporal dependence. However, some things to keep in mind: 1. Modifying the internal solution can lead to significant solver instabilities, especially for a problem with highly nonlinear reactive melt transport. 2. Accordingly, it will take a large amount of testing and debugging to get this to work properly (if at all). As such, I recommend first considering whether you can achieve the same time-dependent behavior through changes to boundary conditions, which already have the ability to handle time-dependent functions. Cheers, John --- _[View the full topic](https://community.geodynamics.org/t/simulating-multi-stage-magma-intrusion-in-aspect-how-to-dynamically-update-t-composition-in-specific-spacetime-domains/3990)._