A federal judge Tuesday sentenced Samantha Leialoha Watanabe to four months of confinement — one behind bars — for assaulting her toddler aboard an Alaska Airlines flight to Honolulu last year.

U.S. Magistrate Judge Kevin S.C. Chang told Watanabe she has to spend one month of her sentence behind bars. The other three months will be under home confinement. After that she will be under court supervision for a year. Chang gave her until Tuesday to turn herself in.

Watanabe’s lawyers said they will file legal papers to suspend the sentence while they appeal the conviction. They had previously asked Chang for a new trial. Chang rejected the request and two others to reconsider.

A jury found Watanabe, 38, guilty in December of simple assault of a person younger than 16 years old aboard an aircraft.

Other passengers and flight crew aboard the May 3, 2015, Alaska Airlines flight 870 from Anchorage testified that they saw Watanabe pull out her then 15-month-old daughter’s hair and slap and hit the toddler on the front and back of the head with her hand and with a stuffed doll. They said the blows were hard enough to snap the girl’s head fully forward and backward. The passengers also testified they saw Watanabe knock her daughter off her lap into the next seat and repeatedly pick up and slam the girl down.

Assistant U.S. Attorney Marc Wallenstein told Chang that the state Child Welfare Services has had to intervene numerous times with Watanabe. He said Watanabe no longer has custody of the girl and has had five other children taken away, and her parental rights have been terminated.

First Assistant Federal Public Defender Alexander Silvert told Chang that Watanabe has been involved with CWS for quite some time. He said Watanabe gave birth to her seventh child, a boy, last month. She relinquished custody to the boy’s father but visits her son to breast-feed him, he said.

Silvert said Watanabe comes from a family of abuse, low education and drug problems, and has gone homeless to get away from that environment. However, since coming under federal court supervision last year, he said, Watanabe has completed anger management training and has received drug and mental health treatment. He asked Chang to sentence Watanabe to probation.

Chang acknowledged the progress Watanabe has made while under court supervision. He noted that Watanabe has not tested positive for drug use and that her son also tested negative at birth. But he said handing down a sentence without a jail term would minimize the seriousness of Watanabe’s crime.