# Can Injection Model Replenish the Filaments in Weak Magnetic Environment?

## TL;DR

This study investigates whether injection of chromospheric material can replenish filaments in weak magnetic environments, finding it effective for active region filaments but unlikely for higher quiescent filaments.

## Contribution

It provides observational evidence on the limitations of the injection model for filament formation in weak magnetic fields, especially for quiescent filaments.

## Key findings

- Injection can lift material up to 10 Mm in weak magnetic fields.
- Heating causes acceleration of about -0.017 km/s^2.
- Injection model is ineffective for quiescent filaments above 25 Mm.

## Abstract

We observed an H$\alpha$ surge occurred in the active region NOAA 12401 on 2015 August 17, and discuss its trigger mechanism, kinematic and thermal properties. It is suggested that this surge is caused by a chromospheric reconnection which ejects cool and dense material with the transverse velocity about 21-28 km s$^{-1}$ and the initial doppler velocity of 12 km s$^{-1}$. This surge is similar to the injection of newly formed filament materials from their footpoints, except that the surge here occurred in a relatively weak magnetic environment of ~100 G. Thus we discuss the possibility of filament material replenishment via the erupting mass in such a weak magnetic field, which is often associated with quiescent filaments. It is found that the local plasma can be heated up to about 1.3 times of original temperature, which results in an acceleration about -0.017 km s$^{-2}$. It can lift the dense material up to 10 Mm and higher with a inclination angle smaller than 50$^{\circ}$, namely typical height of active region filaments. But it can hardly inject the material up to those filaments higher than 25 Mm, namely some quiescent filaments. Thus we think injection model does not work well in the formation of quiescent filaments.